I have a fairly large stash now, so I usually, though not always, start with the fabric. I get a "feel" for what pattern will suit it. Then I start looking through books and magazines with only that group of fabrics in mind, something will usually jump out at me, if not, I don't force it, I will just keep looking maybe for weeks before I find just the right way to use the fabric. If I do see a pattern I love, I will go to my stash and look through it with that pattern in mind and see if some group of fabrics "jump" out at me. I have my fabric stored in groups that I intend to use together, so it is easier to envision them in a quilt without going through all my fabrics individually. Once I have the basic idea and fabrics set, I might need to add to the fabrics or take something out that doesn't work. This is the most fun part of quilting for me.