Judging from your gallery I see you're a fan of Hetalia and MLP. I'll warn you ahead of time that if you get too crazy about how much you like those shows it'll start to irritate people. You're free to like it, but don't go overboard about it.
If you feel like you aren't progressing as much as you'd want to skill-wise, I'd suggest looking into getting other artists to critique your more serious work. It always helps to get a second opinion and there are a good number of people who could point you in the right direction. And remember that most people who offer critique are really only looking to help you get better (this is a point that gets forgotten from time to time).