I think I might just be done. I'm not sure how I can improve it from my skill :/
you can apply smooth shading on certain parts. (even if it's for blockland, you can smooth shade just to learn your way around google sketchup's features.)
how you do this is:
select the faces which you wish to smooth shade
go to: window>soften edges
slide the bar from left to right to adjust smooth shading. (i personally usually stick to around the middle, because i find that the far right is a little too extreme)