Keep it up, man 
Thanks!
Ok, I tried bobbing motion as eishiya advised. And now cant decide which option is better:

From left to right:
1. Bobbing
2. Bobbing again, but with short cicle - I just removed half of frames, so hair, tail and water mirror animations are broken
3. Previous option, just for difference
And I'm still trying to create a horizontal movement, as Adam advised.
Also, succubus animation:

And I tryed to animate tree and grass:

What you think, guys? I think option without flying leafs is better. And animated grass looking bad, so maybe I should leave it static.