Learn anatomy. Learn perspective. Learn color theory. I would suggest you join conceptart.org. Create art, post it on there and get feedback and critique from other artists. I think it's a great way to learn and improve.
Isn't Super Meat Boy entirely pixel art? I wouldn't knock pixel art, if you've never created art before, creating pixel art similar to the SNES would be a lot easier than creating high res art that looks like it's straighy outta Rayman Origins. I recommend joining pixelation.org and pixeljoint.com if you want to learn pixel art. Lots of great artists on there happy to help you improve your craft.
Read the animators survival kit by Richard Williams to learn how to animate like a boss.