/ic/ - Artwork/Critique

Complete beginner here. Never posted on /ic/ before.
I draw at most two drawings a year whenever I feel a surge of inspiration. I've only filled one sketchbook since 2008. Today I went out and purchased a nice mechanical pencil and sketchbook to actually start attempting to get good at drawing. I know there's a very comprehensive sticky, but I lack the motivation to grind through most of it. If anyone can point out how I can improve quickly based on work I've already done, that would be really useful. I'm more interested in drawing in an anime/manga style, if that changes anything.
Pic related are the only notable things I've done in practically my entire life. Not very proud of the most recent one, but it's the only thing I've drawn this year so I thought I'd include it. Everything was drawn from a reference.