When I first started, I would put together a group of fabrics, first choosing my focus (usually a print of some kind) and then build around that for a cohesive palette. I was not shopping for a specific quilt necessarily - but would end up with a stack of fabrics that I liked and went well together. I find I use some colors almost all of the time, so now shop for variety in those colors. As I see a print that I really like, I now will usually have a lot of the fabrics I need to fill out the project with just a few additions. Eventually, you have some of every color - and not much of stuff you don't really like. I shy away from precuts as I find them very limiting - fat quarter bundles will find their way into my stash from time to time though. I avoid garage sales and other methods of acquiring fabric, as although it may be cheap, it will sit unused and unloved until I just get rid of it.