"It was 1989, I was in graduate school and some friends were getting married. The question — what to give as a gift ? Well... what does any artist give when they don't have much cash ? — their art. So, my present was to photograph their wedding. It was a wonderful wedding/costume party. The groom came as a frog, the bride came as a bird, and I came as a 1950s photographer: a short sleeve white shirt, a bow tie, and a Fedora hat with a press pass stuck in the brim." — Michael Shuter.
General advice
If you are asked to take pictures for a wedding because you are the 'photographer of the family', my first advice is: don't. Weasel your way out of it if you can.
It's a big responsibility, and unless you are pretty sure they won't hate you for life for screwing up, you're better off letting somebody else take care of the baby and the bathwater. But at the same time it makes for a great wedding gift they'll still remember in their retirement home. So if you still want a go at it, here's some advice I have gathered from the 15 or so weddings I have 'performed'. It's advice for amateurs, certainly not for pro wedding photographers who are in a whole different category. But you have one thing above the pros: they usually shoot only the ceremony and the portraits. You can do a lot more for the entire day. And whatever you do, don't ask for money, it will take a lot of pressure off of you.
A couple weeks/days before:
Ask for the timetable of the day.
Ask what kind of pics they want. Whether they want B&W. Don't listen when they say 'We don't want the classic wedding pics'. For one they'll regret it. For two if they have a classic wedding, classic wedding pics is all they'll ever get, unless you drop acid before you start shooting.
Check beforehand what's allowed (flash in the church, getting close during the ceremony, getting on the other side of the pulpit...)
Clean you lenses and sensors beforehand. Check that the flash battery contacts are clean and that there isn't any leakage.
Right: Groups are easy to take... if everybody has eyes open, and is looking in the proper direction.
During the day:
Regularly check your settings: 400/100 iso when going in/out. What is the current focus mode and area ? What's the current exposure mode, area and compensation level ? Force yourself to read all the stuff written on your screen when you have a second. Don't know what that blinking 'R' in the corner means ? Too late, maybe you should've spent an hour or so re-reading the user manual a week ago just for a refresh.
Regularly check your results: How is the focus on the last pic ? Can you tell the difference between out of focus and blurry moved ? How was the exposure on the last shot, are there burnt / black areas (learn to read a histogram) ? Remember to check.
When the light is good, take the pics now, don't assume it will stay like that later when everybody is ready.
Charge all your batteries beforehand. You have more than one, right ? Bring extra batteries for the flashes. And more batteries.
Enough memory cards ? You will NOT have time to unload them to your laptop. As of 2009, a 16Gb CF card costs 20$, but that's only about 300 good quality RAW pics. Barely 5 pics per minute for an hour. Don't be cheap, your camera gear costs at least 50 times more: so get more memory !
You weren't thinking about doing the pics in JPEG, were you ?!? RAW all the way, it's the only way to fix complex lightings (flash + neons + sunlight through window), to get precise skin tones and to have adjustable contrast.
B&W portraits are often nice but above all they are a very good fallback in case the light is no good or in case the background is all concrete and power lines. Try not to mix color and black and white too much. With digital it's easy, shoot everything in color and convert to B&W in your RAW converter, weighting on the red channel which gives cleaner skins.
Walk around to try to notice new perspectives. Are there stairs you can go up somewhere ? Can you go out and look inside through a window ?
Think about the surroundings, the church seen from outside, the kids playing in the back... Just make sure you are not busy photographing the church door right when you hear 'I do!'
Use the natural light whenever possible: a beam of sunlight coming through a high church window ? Great, ask them to stand in it.
Always plan out what's coming next: the 'yes', the rings, the kiss, the speeches, the exit, the rice/petal toss, the cake cut, the first fight, etc... and take positions and change settings accordingly.
It's OK to forget a few people in a big wedding, but make sure you don't favor one family over the other, at the risk of offending them. Particularly if one side is much smaller than the other. Figure out early whose side people are with. Ask the couple for a quick rundown as early as possible and try to remember who you already shot. Ask them who the important people are.
Does the bride or groom always have the same expression ? Try to get him/her to change by firing off a few wisecracks. Or ask him to close his mouth if the reason is a too deep cleavage on the bride.
Act confident, they are probably more at a loss than you are anyway, and the groom needs to get used to being told what to do in any case.
Watch for the real pro who shoots the wedding unasked for, hoping to cash in later. You are the photographer, so don't let him step on you (but there's no harm in letting him work alongside, sabotage isn't nice).
Deodorant for you ! You'll sweat as much as a groom at a shotgun wedding.
Equipment advice
Right: A few specialty filters or lenses such as the LensBaby can help, but it's easy to overdo it. A few pics like that are enough.
Make sure you know your equipment inside out particularly the FLASH system, something that usually gets forgotten but that comes in full force for weddings, be it pics inside dark churches or portraits outdoors with too much sun (hence too much shadow that needs clearing).
Bring an extra body (one carrying a wide angle zoom, the other with a telezoom). And if you can't, at least bring a good quality compact you can use as a backup. Can you really do the whole wedding on that compact if you drop your SLR in the morning ? Think about it. My 8 month pregnant sister fell down the stairs carrying 4 cameras the morning of _my_ wedding, breaking all of them... If you use more than one model of camera, be prepared for lots of post-processing to match their looks.
Synchronize the time on your cameras otherwise sorting out the pics will be a bitch.
Bring an extra flash: twice I've had battery leakage right during the ceremony, from too much power drain.
Batteries and extra batteries. Rechargeable are faster for flash but don't last as long as good lithium alkalines.
Where are you gonna keep your gear ? It's heavy to carry around but do you want to worry about theft while you are busy shooting ? I've had a tripod stolen this way, but those creeps forgot that I had the head still attached to the camera. Grad a bored teenager, give him the title of assistant photographer and let him proudly carry the spare gear around !
Technique tips
Right: Just a different view to what everybody else can see.
For outdoor portraits, use an assistant and a large folding reflector instead of a flash. Or both.
Use a diffusor on the flash in order to avoid hard reflections. If you don't want to invest, a piece of white plastic or even a sheet can do.
Be bossy when taking group pictures: don't hesitate to order or even push people around, you know the usual, having to push back the mother in law who is 2 steps in front of everybody else, put small people in the front, kick tall ones to the back, etc... You'll need to scream your lungs off to gather all the cousins who are too busy drinking Champagne on the other side of the park.
Take multiples of each group pics, do a quick verification to check for closed eyes. Some recent cameras can do that automagically.
For the official portraits, do some role reversal, otherwise you may end up with pics of the groom looming much taller than the bride on every pic. If they stand like stick figures and you don't know how to get them to pose, make them move: kneel, walk around you, lay in the grass, kiss hands, blow in the ear of the other, whatever shakes them up. That's the crucial time when you need to act confident.
Multiflash would be nice to have in a large dark place like a church, but it's oh so difficult to setup. And you'll be moving around a lot. At most, place a remote flash in the center pointing at the ceiling. Make sure the flash itself is not in your field of view.
Think about bounce flash, but not if the ceiling isn't white or is too far up.
In a dark church, I find that the best setting is to use manual exposure, with an almost completely wide exposure and a speed set so that the result is only slightly underexposed (say, half a stop). Raise the ISO sensitivity so that you won't go below 1/15s with stabilizer or 1/45s without (or use auto-ISO), then add a TTL flash to that. Pay attention to the color temperature in post-processing.
Lenses. Well, I would put less importance on lenses than for other types of photography such as landscape. You need all the sharpness you can get for group photos, but for the rest the most important aspect is the aperture since you'll be operating indoors. So I'd recommend a 24-70 and a 70-200 f2.8 zoom 24x36 equivalent. Don't take too many lenses and gear or your shoulder will remember the day more than the newlyweds will. Sure you can dream about a defocusing lens for the portraits, but just forget it for now, mkay ?
Even if you check your portraits on the LCD, they may still be off for various reasons (eyes looking the wrong way, wrong expression, etc), so take multiples. The more people on the shot the more you'll need.
Day planning
Contact the bride and groom beforehand to know how they plan to organize things and how much time you'll have at each stage. Get them to set aside at least 30 minutes for isolated portrait shots when they can relax and don't need to run around with other things to do. Make sure they understand that and that nobody else is tagging along.
I like to organize the day pics in the following subsets:
Right: Flying rice and rose petals: be ready as it lasts only about 2 seconds.
The dressing up
Mostly of the bride but also of the groom (he's usually a lot more stressed out, so it can be more fun. Remember the paperbag trick when he's about to pass out from hyperventilation. Just kidding). It's not always easy to be accepted during the bride's dress up and showing pics of previous event helps a lot, so you may have to get out when she changes underwear. In any case it's fun and well worth it, until you get thrown out by the bridesmaids.
The ceremony
That's the important part but it's not where you can take the best pics: usually the light sucks and you need to bring up the sensitivity. Also the priests/mayor sometimes looks at you hard when you walk around; just ignore them and do what you need to do. Wear quiet shoes. Don't max out your ISOs for the first time if you don't know what to expect. Pay attention to the timing, in some busy cities the ceremony lasts less than 15 minutes from entering to leaving the place.
The exit
When coming out, remember to LOWER the iso setting. Lay low with a wide angle and the flash so you have a good perspective on the stuff thrown on them. It can be pretty chaotic and very quick.
The cocktail
Walk to the various groups of people talking and drinking and kindly ask them for a pic. Be quick and move to the next group. Refrain from showing your big zoom to the pretty 2nd degree cousin.
The group pics
Possibly during the cocktail or right after getting out of the ceremony. Do some with the bridesmaids, with the best men, with both, with the close parents, with the bride's extended family, with the groom's family, with the friends of each side, with the coworkers, the bridge club, the golf buddies or any group they can think of (ask them in advance). Use a tripod as it gives them a point of reference as well as sharper images. Use a direct flash without reflector or you won't have enough power. If it's sunny, turn them so the sun is about 45deg from their face.
The portraits
Reckon a nice place in advance, with flowers if possible. Use an assistant holding a reflector and teach him to clear out the shadows. Try to time it in order to get a good light (2 hours before sunset is a good bet). You NEED to get away from the crowds and don't let anyone come close, it just distracts them. If you are in an urban setting, check the area beforehand to find a park.
The tables during dinner
Doing portraits of people with wine noses and too many bottles in front of them doesn't usually yield great results, but this way you can be sure to have captured everyone. Let the newlyweds walk to each table to salute the invitees and stand on the other side with a wide angle. If the ceiling is white, use bounce flash.
The party
Let your creativity show: stroboscopy, flash + long exp, black light on the bride's dress, etc... Try not to be too drunk by that time, you'll have time to catch up later. And you can pick up on the girls who already inquire if you are available... for their wedding, even though they don't even have a victim in mind yet.
The backup
Before going to bed, yes.
The RAW processing
Takes longer than the wedding day.
Final results
Finally, the images are taken, processed, archived, backed up and ready. What do you do with them ? I do the following 'services':
A public website with all images (or just a selection) in small format.
A private website with the images in full resolution just for the bride and groom and whoever they want to give the URL to. I usually use Gallery2 to present images on my own server, but Picassa or any image hosting will do fine (make sure they don't have screwy terms of service though).
A photo album built online through one of the many photo retailers. Don't put any comments on it, just their names and the date.
Some large prints on quality paper.
A backup CD/DVD. Maybe a cheap USB key with mid-resolution images so they can be viewed directly on recent USB-enabled TV sets.
Left: Interesting dark light effect on the wedding dress.