I would take the background off and either paint it black on the back, paint it blue or just leave it clear.
Then get black sand or white sand. I use black sand alot in my tanks. I have a 93 gallon cube that I am going to put white sand in soon.
Then go with a natural look. Drift wood, native stone and live plants. If you cant find real drift wood, go with fake or even take pine tree branches, strip the bark off and soak in water for a few weeks and that will look good. You can even after soaking in water a few weeks, let it dry out 100% and clear lacker it so it stays clean looking and the lacker will give it a light driftwood look. Just make sure you use water safe lacker.
Live plants will look really good, but for now, I wouldnt buy any. Your tank wont support them rt now till its established and there is plenty of food for them. So get the fish you decided you want, and after a few months of the fish being in there, add the plants. Make sure the plants have good lighting...