Some good advice here ^^ I only have a few tips:
-Draw from real life. It's one of the greatest practices you can do. It'll help with characters, backgrounds, inanimate objects, and subtle details. If you're into animation, it'll help you learn how things move.
-Study human anatomy. You don't have to take a full class (I did and only about 9 weeks worth effected my drawing u_u), but get and pictures books that teach you the skeleton, muscles, and overall figure - it'll help your proportion. You don't have to read the words if you don't want to, but I make it a habit to read them at least twice.
-Copy/trace different types of professional artists with different styles. Doing so with your favorite artist(s) is fine, but you may find it easier to create your own style if your not heavily influenced by 1-2 artists (this may not be the case if you have like a nice amount of artists). You may also find that the artist(s) you were soo sure you didn't like has a nice way of drawing ears ^-^
-Make your own character(s). Create a character that you like. Whether it be a future character in a comic or just an ideal person you'd like to know make a basic outline of them. Then keep drawing them. Even as you practice with whatever method you're comfortable with, keep going back to them and improving them with the new methods you learn. This way it'll be your character that gets the best of your learning instead of an already created character =)
-Don't hesitate to draw your anime/real character in a realistic/anime form. Good way to practice - interesting too ^^