Hi. A way to decided what to FUSSY CUT is to take a piece of paper, and in the center of the paper mark the size of the FINISHED block, cut that out from the paper. Now you will have a piece with a hole in it . Then around that mark your prefered seam allowance. You can then take that paper and slide it around your chosen fabric and select a design that you want to feature.
Say your fabric is floral that you like but the flowers might get "lost" if you just cut. With your paper you can slide until you get the flower you like in your cut opening, then lightly mark what you want. That will be what you will cut be sure to add your seam allowance.
You'll end up with a lot of scraps but those can be used in another "scrappy project".