...You are kidding, right?
What you need to improve:
Most important: Practice, practice, practice!! But that one you are doing just fine :)
Secondly: Grow some age. If you are under 16, you have no change making anything good.
Then what you must do:
Practice drawing, get a humanish model and draw replica of it.
Leave the stick figures out.
Clouds and other bg object, make 'em more alive. Moving, not sticked on the screen.
Plot. Make something interesting.
If you can draw to paper, you can draw it with computer. More practice! Draw different objects and scripts.
If you wish to make easier animations first, find gameoverse series on the newgrounds, and take sample from it. Don't try to copy the same idea, but you can use the same style. Flash doesn't need to be all good graphic to be good. Plot is the main what matters.