One way I found helpful to learn about colors, values, and dealing with scraps is by making multiple blocks of the same block, but different fabric placement. They can go together as a sampler if you feel you need a use for the practice. Vary where you put the darks/lights or colors. It can bring out different aspects of the design you didn't notice, or make something with a 3D effect otherwise missing. Do a search on Farmer's Daughter quilt block to see some examples of how different placement can change stuff.
One of the things about the B&W photo is it mostly helps with value, how intense a color is in comparison with others. We are sort of used to thinking of "yellow" as being the same as "light" but why the block isn't working may be because it is in comparison dark to the others.