All diagramming concepts are important for drills. If you want to try to get through it more quickly, however, I would recommend focusing on sufficient and necessary, the contrapositive, the diagramming of: if/only if/only/if and only if/No Xs are Ys/not both/unless/all/either/or, and the diagramming of compound statements.
Hope this helps! Sorry, I know that's a lot. But for diagramming, there's a lot to learn!
