I don't know what to do with the leaves, because I don't understand how they grow on a tree.

Do you live somewhere without trees?  If not, go look at one.  The best way to see how they connect to the tree is to lie down with your head touching the trunk.  Then look straight up.

Scaling is unnecessary and can be detrimental on this forum.  We can click on any image to scale them.  If you pre-scale your image that gives us less control over the size that we see.  Additionally, if you pre-scale your image then you make it harder for people to provide you with helpful edits.

Well it seems that you are going to do a major rework inspired by Atnas's edit, but here are my thoughts on what you did so far:

In your original picture he looked like a muscle baby.  There are a few reasons.  The first is the large head.  You can get away with a large head (to provide a distinct and expressive head) but it is going to eat away at your muscle baby budget, so you have to be extra careful on the rest of the sprite if you don't want it to look like a baby.

The next is that his shoulders are slightly narrower than his hips once you factor in foreshortening.  Men have shoulders that are wider than hips, women have hips that are wider than their shoulders, and young children about equal.  Your fiancee seems to have partially picked up on this when she recommended narrowing the hips.  However that just made it look like he had big thighs, a trait indicating that he is a mature woman.

Third, your sprite has big feet in proportion to his leg, which is another baby trait.

I really like the one where the water is moving downstream.

The ripples are moving away from the rocks, as if the rocks themselves are generating the water.  Would it be possible to work it so that the ripples alternate between moving towards and away from the rocks?  This would make it seem like the water is sloshing around.