I don't know how you are about colors and patterns, but if you are like me, just get what hits your fancy. However, since you are new. I would only buy fabric for the project that you are working on, well at least until you get the QD that we all have. Right now I am slowly starting to build a stash. I get just what I like. I don't have lots of money to spend on fabric but I buy just a little extra than what I might need for a project. that way any extra can be used for another quilt.
as for the cutting I just starch and fold my fabric then cut the way that will give me the best shapes for what I am working on. It does matter a little, but that is mostly for certain projects. good luck and I hope that you really enjoy quilting. this board is the best for asking all sorts of questions.