Well I do have some advice that could help after looking at those pics.
Junk it up a bit! Add clutter, vines, toilet paper rolls (if hes small enough), anything that gives the little fella more places to hide or to at least let him feel more secure. I prefer hanging vines all over the place but if you get vines go to a craft store, they are MUCH cheaper.
Secondly I would recommend covering at least the back side of the tank. In reality you should try to cover 3 sides. There are a number of ways to do this ranging from the expensive stuff at pet shops to simple construction paper! Hell, I have even heard that some people will tape pictures on the glass/plastic/plexi to make the snake feel more secure.