1) Bring Lots of Batteries
This is especially important for digital camera users since digital uses more power than film. And if like most guests with digital cameras you're showing your pictures to others at the wedding and reception, that LCD will zap the power even more. So pack lots of extra batteries.
2) Bring Extra Memory Cards and Increase the Resolution
You never know which pictures will end up being the ones you want to frame or make prints of for the photo album, so be sure that your camera is set to medium or better yet, high resolution. Extra memory cards will ensure you don't run out of space.
3) Look for the Unexpected Moments
Along with all the traditional moments that you don't want to miss: the bride (or groom) getting ready, the exchange of vows, the first kiss, the cake cutting ceremony and so on, there are bound to be many unexpected "Kodak moments." Watch the children as they will provide many sweet and comical photo ops at a wedding! And don't forget to honor the parents of the bride and groom with pictures. There will be much emotion on this joyous day to capture with your camera.
4) Increase the ISO
If you have a film camera, use a higher speed film, such as 400, but if you have a digital camera like most will, increase the camera's ISO, that is its sensitivity to light. Try increasing just to 200 or 400. Use digital noise removing software if needed. The higher ISO can brighten otherwise underexposed photos better than a compact's built-in flash.
5) Photo Edit Out the Red Eye
Most wedding pictures are taken from too far a distance for the camera's red eye reduction to work, but photo editing software such as Photoshop and even the free, Picasa can take the red out.
6) Save the Flash for the Most Important Pictures
Since it can take flash a while to recharge, plan ahead. Unless a "can't miss" spontaneous photo opportunity comes up, save the flash for moments you most want to have pictures of, like the bride and groom cutting the cake, kissing after their vows, their first dance, etc.
7) Make Use of Optical Zoom or Your Feet
For those far away shots, use optical not digital zoom if you can. If your camera doesn't have optical zoom, and you can physically move in closer this is the better choice.
8) Don't Let Shutter Lag Ruin your Pictures
While this isn't a problem with film, if you are shooting with a digital camera, be prepared to compensate for the shutter lag. Some cameras shoot much faster (or slower) than others, so if you haven't done so yet, get acquainted with yours before the wedding.
When taking action shots such as dancing at the reception, do the same as you would at a sports event. Try to anticipate what's happening next, point the camera in that direction and press the shutter half way down. Be ready to take lots of pictures where there's people in motion, so that you end up with several keepers. And on such an important occasion, it's a good idea to take several of the still shots as well.
Hopefully these eight wedding photography tips will help you make the most out of taking pictures at your next wedding. Until then, keep practicing and have fun learning photography!