I am completely new to pixel art, but I'll be making a ton of material for a possible RMXP game. Taking some baby steps into the realm of pixel and spriting I decided to start with icons since they are only 24x24 pixels. They are so small and yet their size gets two opposing reactions from me.

"It's small so it should be easier. It won't be as taxing as a large and elaborate painting or drawing."
"IT'S SOOoo small! I change one pixel in one area and it changes everything! What do I do with this tiny canvas!?"

So... I produced a few icons still very much WIPs since I can tell they need work, but the more I mess with them the worse they look at this point. I need some tips on how to make them better.
Don't tell me a statement without explanation please. I know that the two on the second row need much more contrast to stand out and many need more proper shading, but give me something specific about working with pixels not just the basic art concepts.

Anyway, here they are!


The icons are as follows, left to right, top to bottom:
Lightning Magic
Shark Mask
Lich Mask
Vampire Bat Mask
Chi, a living doll which heals.
Chi (2nd version)

The masks will have usable skill sets for one of the main characters.
These are for my game only.