There are 4 things I would like to share about working with scraps:
Thing One: Unity
When working with scraps there can be a unity problem...they can look disjointed/scrambled/in-cohesive. Now the ladies in Gees Bend don't have this problem. They work with the theory, if you cut it up small enough everything goes. However, they also balance color, line, and shape across their work to create unity. You can work this way also. However, if you like a more organized or matching look don't rule out working with scraps. You just need to organize a bit before hand. Sort your scraps into pleasing color combinations. Think easy palettes: spring, fall, winter, Christmas, Halloween... Or maybe cool colors (green, blue and purple) and warm colors (red, yellow, and orange). Or get out your color wheel and experiment with new combinations. You can always add another fabric (solid or print) at act as a unifying agent.
Thing Two: Be Prepared
It is easy to complete a scrap quilt while piecing a planned project if you always keep the scrap pieces next to your machine. Bonnie Hunter calls them "leaders and enders". Many people use a scrap of material when starting to piece/strip piecing. It helps with keeping the pieces from getting pulled down into the feed dogs and eliminates thread tails. Instead of using a scrap piece, use a pair of scrap blocks. Do your strip piecing for your planned quilt, then at the end of the strip add another set of scrap blocks. Cut off the planned blocks while leaving the scrap blocks under the needle and foot of the machine. This set of scrap blocks then becomes the leader for the start of the next set of planned blocks. Just set aside the scrap blocks as you complete them. Eventually they become a project unto themselves.
Keep strips of leftover fabric together. Keep squares of leftover fabric together. I recommend picking either sizes based on 2" or 3", so you can build blocks of either 4", 6", and 8" or 6", 9" or 12".
Thing Three: Build It
If your pieces aren't big enough, you can piece your fabric. Strip piece to create your own striped fabric. Use blocks to create checkered fabric. Use triangles. Crazy piece it. Make your own fabric... improvise. In the words of Tim Gunn "make it work!"
Thing Four: Keep It Simple
There are enough basic blocks and combinations to keep things interesting, especially if you make your own fabric. Think about it...
If you just worked with stripes: Rail fence, Roman Coins, Log Cabin, Pineapples, Chervons. Now, what if cut a strip of striped fabric and used it in place of log or rail... or substituted a row of half triangle squares for a log or rail...
The same is true if you are working with a four patch or half triangle squares!