ok!
I'm gonna go back a bit. First of all, having a reference can be helpful and all, however going straight off it it's not always a good thing, especially when it's cartoony like this piece.
The problem here is the translation to pixelart, It gets very weird.
Now if you want to do it straight off anyway there are a cupple of things you need to think about.
The outlines around the tree make less use in this format. The only purpose it serves right now is to make it look sharp and edgy, not in a good way and far from the original reference. It's ofc achieveable, but it would take plenty a colours for AA, which is just not needed. Also when you are using outlines like this, you don't want to put them "inside" the sprite. Like, between the bright piece of leaves and the dark parts, there is already a contrast which is not needed to show further, same goes for the trunk.
And it looking empty is not a problem
I made a very sloppy edit to show you this:
I also made a version so you might compare this to something, I'm sure there will be plenty of Palmtrees around the forums aswell.
Jad made this edit of one of
jedzeds art:
Keep it up and good luck!