Yeh, I know the layout is a bit awkward. The original place was to place the taller plants strategically around the spong filter, hence the amazon sword and some of the taller sprites. Then it's supposed to curve around to the back row and continue to the end of the other side(the not so tall sprites). The idea was the have the driftwood as the center-piece, a little off to the side on the left(where it is now) and have everything around the driftwood, empty. That'll be the feeding area, where the inverts would come out of hiding and feast. Would make great photo ops as well. As you can see, that plan changed a bit when I didn't know where to put the moss, and the fern. They may be temporary, or re-arranged.i agree with a black background. It would make your plants pop out!
i use the very basic method of the rule of thirds to decorate. I am not sure how big your tank is, but take a 10g for example. At the 1/3 or 2/3 mark in the tank i put my focal point, which would be 6 2/3 inches from either end of the tank. You have the awesome driftwood, and the to broad leafed plants that all seem to draw the eye. Unfortunately it draws you to two ends, spiting your focus. If you rearranged and put the broad leafed plants around or near the driftwood, it would draw your eye to one place. the water sprite would make for a nice background and filler around your focal point.
Keep up the good work!