-Snipetysnip-
That doesn't look that bad.
It's plain, nearly empty, and looks bad.
This, though. So much this.
Anyways, just learn how to make different obstacles such as in my Ubran TDM, I have couches on roads tipped over, chairs, etc. You just have to understand what theme it is.
If all else fails, I suggest fiddling with terrain bricks. I've heard they can make some flat grounds into nice bunkers etc.