Study the pattern to understand what number and sizes of patches it calls for, taking notes to keep track and cut what's needed from your yardage.
I'm very glad I did that with one popular fat quarter pattern because I learned that out of 40 blocks used to make the quilt, the distribution was 16 of block A, 12 of block B, and 12 of block C. It bothered me that there were 4 more of block A than the other two. Plus at 40 blocks (5 x 8 setting), the quilt was way longer than it was wide, and I didn't care for that either. I ended up making 42 blocks (6 x 7 setting), 14 of each.
I went through a fat quarter buying stage, but now rarely buy them. If you can figure out how to convert one pattern, you will be able to do so with your second and third patterns, etc., and use up your yardage.