For draws, get 8-10 shoulder-length slings (24" or 60cm), plus a couple of double-length (48" or 120cm). The double-length draws come in handy for slinging trees, chickenheads and such, and can also be used for 2-bolt anchors.
There are two common ways to handle the single-length draws. Some people like to clip a biner to them and carry them over the shoulder, and then carry extra biners. The other way (my preference) is to put two biners on them and carry them tripled over, usually on the harness -- the so-called "trad draw". Each way has its pros and cons -- you probably have partners who do it both ways, ask them why and then decide for yourself. Carrying a couple extra biners for anchor stuff is a good plan in either case.
Some people like to use wiregates on everything. I prefer solid gates on the pro side of the trad draw and wire on the rope side. I am just anal that way