a) Yes, practice a lot, and I do mean a lot.
Aimless practiuse is the worst thing you can do. Probably you'll learn stuff wrong and won't be able to fix them or worse, fuck up your arm or something. Consult a teacher about proper playing position. You'd be really suprised how many people play completely wrong and risk tendon injuries all the time. Warm up before you play. Warm up right, practise right, and practise STUFF, not just aimlessly playing sixteenths against a metronome. Although a metronome would be good.
Perndog's about right on everything else. Understanding HOW chords work is much more important than actually knowing a fuckload of them.