Hello! *waves*

My boyfriend, me, and three of our friends are making an RPG together. My BF (the main leader), wants our character portraits pixel-based. Based on some opinions (from the first, old demo), they mentioned the edges of the portraits were jagged.

We're both artsy people. We both drawn and pixel. He's more talented than I am, so he's doing the art. However, since he's supposed to be doing tilesets AND programming, I thought I'd try to improve the portraits myself.

Of course, I have no idea where to begin. For reference, here is the portrait:



Some notes:
 1) This is the size it will be in game. Maybe it is too big?

 2) On my computer it's hard to see the skin tones, but it's fine on his computer. I think something could be fixed there.

 3) Should bigger portraits have more color instead of less? I know he chose less because it's easier to edit.

 4) Of course, how can I make things more... "smooth"? I've heard of anti-aliasing, but I wonder how that relates to pixel art?

Thanks for any help in advance!