Edited your jaggies, played with your palette, and showed some inconsistency with your shading:
Where is your lightsource? Currently you've got every post's shadow going in two different directions, which is only possible if you have two lightsources.
Also, wood is not that orange
I desaturated it a bit.
Now, if you're going to do the woodgrain on the posts, you should do it throughout for consistency. Right now it looks like the only wood is the shadows of the posts.
'Kay, so my tip for the jaggies.
The top line is the basis for isometrics. You get that, good.
The bottom one, where it alternates between 2 and 1 pixels, is an in-between type of line. You'd want to avoid it in iso art, but when you're doing a curve you'll probably use it at some point. That's what I did. What was in yours was uneven spacing between the 1 pixels and the 2s, which made it look jagged. (Not too good at explaining... try stacking mine on top of or next to yours and seeing exactly what I did)
But like Atnas said, immense improvement over the skull.
