Most characters are broken down into components on the right hand side. Whenever there is a component that seems to be pretty important to learn individually, I like to add it to my study list -- so that I can make better use of the mnemonics.
Feature: Perhaps, it'd be possible to prioritize the components? For example, "Add with high priority" -- or at least higher priority than the character I'm currently learning, so that I can focus on the more basic parts first.
For example, lets say I'm learning the word 鲜,I'd like to be able to add 鱼 and 羊 to my list (which I can currently do. But the part I'd like to do is learn those smaller two parts first.