I am shooting a wedding for my sister in law for free. It is going to be a laidback wedding. I just wanted to toss this out here and ask everyone to give their #1 most important piece of advice they could give for a first time wedding shooter. Keep in mind that this will be slightly traditional but not overly formal. I will be shooting with a Canon T1i with a Sunpak PZ42X flash and I will probably mostly use my 50mm F/1.4 lense. I am going to order a grip and two extra batteries ( so I will have a total of 4 ) and will have 2 16gb cards with a few 2gb cards as a backup.