Try using a harder brush, the softer brush is used pretty rarely in general.
Also, are you using a tablet? If not, I think it would help you greatly if you want to get serious with digital drawing. If you have a tablet, trigger the pressure sensitivity.
Also, try to block the colors, there is many tutorial on the web on the subject.
If you want some serious critique, I would suggest heading to 4chans /ic/ and posting on the drawthreads, it's kinda hard getting crits here.