Every tank I see on here that grabs me is some super complicated fertilizer/CO2/watts-per-gallon jungle! I don't really have the resources for that sort of thing
You only need that stuff if you have live plants in your tank. You could create a really nice aquascape with rocks and driftwood. The trick is, is to carefully select the rocks and wood you use to fit with a design. There is a lot of variety out there. And, you often won't find the best rocks at a pet store. Head to your local landscape supply center and have a look around.
Add a few fake plants (get good ones as there is a significant difference in appearance between brands) or some hard-to-kill plants (some types of amazon swords or java fern).
I am not so into the 'creative' decorations. The skull. I think a more pleasing aquarium is created using things that come from natural habitats or at least represent such.
If you really want to get into it, do some googling about visual design principles. They apply to aquarium layouts just as they do to any form of art or creative process.
I'd also agree with the black background comment. Or dark blue. Anything would be better than Batman & Superman.