In my opinion I think you've got manga paneling covered though if you come up with something different or new that would be great. I think of the two I need more work on perspective espeically human anatomy perpective.

i need practice with both, but more on paneling

Yeah, I haven't been around for a while, I know.

but I think perspective would be nice.

I really don't have any trouble with perspective (but I'm one of very very few!) but setting up manga pages would be amazing!

OMG Perspective would be a huuuuuge help XD
It's so nice of you to do these

Probably perspective, I think it's more difficult thing that nees a lot of studying (and good tutorials like yours).

I'd actually like one on your coloring technique - It may be you already have one though

i hope perspective is the one you decide to do. becouse i have never attempted to even try to draw backgrounds. and my people are always funky looking...