When I first started quilting I looked for a picture or a quilt pattern that I liked "as is" and then Found fabrics very similar to the picture. As I got more experience and felt more comfortable with my own ideas, I did what ManiacQuilter suggested--find a focus fabric first, then look for others that coordinate. A focus fabric is your 'primary' fabric that you pick first, the one you want to be the center of attention or has most of the colors in it that you like---usually the largest print. Then start auditioning coordinating fabrics with some of the same colors or hues of your focus fabric, but with contrasting smaller prints, stripes or solids. You will get better with practice. Sometimes you learn by making some really ugly quilts---I did!!!