Thanks for the tips! I doubt I'll pick up the book unless I can find it cheap somewhere IRL, but I'll pose like an idiot in the mirror to get my animation right next time. xD

If I may critique the animation....

This animation is a great beginning, though there are a few areas where you could polish it further.  Remember to always maintain your character's volume - on frame 4 his right foot shouldn't lose height by a pixel.  If you are going to lose the height by a pixel, remember to gain some width so it looks like there is pressure squashing his foot.  His left foot shouldn't move horizontally without a corresponding weight shift in his body - stand up and try to move one of your feet without shifting your body weight to the other foot.  :)

Grab and read the book Disney Animation: The Illusion of Life for lots of tips on how to make awesome animation.

I think it would be a lot more dynamic if his feet stayed in a fixed position and lis legs bent.

 Where's the animation? o.o