Goku Sketch

Dragonball Z has always been one of my favorite animes to watch, so I decided to do a quick sketch of Goku as I'm excited for the new movie, might do one of Vegeta and create a piece out of it. I think I got the perspective wrong for his arm, maybe showing too much of his bicep? Can't quite figure it out. Looking to improve my drawing skills, so comments and critique would be greatly appreciated!