You are going to find this so liberating! When I started my scrap users system, I started cutting up FQs for a Bonnie mystery quilt - pinks, greens, browns, and neutrals. Some of my FQs were over 10 years old. What was I saving them for? If I need a different color or more variety, I now purchase a quarter or third yard piece - usually cheaper than FQs, and just cut the strips I need plus a couple other sizes. Cheaper visit at the LQS, but still get that satisfaction of buying fabric. :-) I mostly cut strips, and for pieces less than 12 inches cut squares. You will be amazed at how quickly it all starts building. i haven't cut many bricks - figured I can cut them from strips if needed. It is so fun to do a scrap quilt and just reach for the pile of whatever strips you need or open the drawer with the squares. I also thought long and hard over what sizes to cut. I cut 1.5", 2", 2.5", and 3.5" strips and squares.
I've even broken into the yardage stash if there is a color I need, but generally try and save the big pieces for borders or pieced backs.
Have fun!!!