Here is a couple sites you can go to to find the most commonly used equipment.
http://www.sullysbowfishing.com/ http://backwaterbowfishing.com/
Most commonly used stuff is ams retriever reel, fiberglass arrows, ams safety slides, and muzzy tips.
You don't really need much for sights and rest set up. I don't use either but some use roller rest and things like that and some use a cheap single pin sight maybe but it doesn't take much to shoot some fish. A bow a couple arrows and your reel.
As far as aiming. Aim low cuz water refracts andif you are missing, aim lower cuz your not aiming low enough. I think the rule is about 3inches lowfor every foot of water the fish is down from the surface.