Any suggestions for this 5g

That's so cool
I love the driftwood tree on the right

A good cleaning.

Yeah, I think just a good cleaning a small rearrangements would be fine. I also like the look of having plants sticking out of the water.

I'd take away those rocks and replace them with something nicer to look at. Also, when you take a picture, just provide some light so we can see better in there.

background? unless you are able to view it from either side.

Better lighting, more substrate and a black background. Emphasis on the black background!

Were you looking for opinions for stocking the tank as well?
If so, lots of lower light plants and one big shockingly beautiful Betta. That would make me realy happy. (I like the colors that come out in fish when the lighting isn't too intense)

As far as Aquascaping is concerned I'd try to keep relativley small plants and rocks up front, unless you want a certain plant or rock to be the centerpiece for the tank. Then keep the larger plants toward the rear to open up the center of the tank and to hide ugly equipment. You'll be able to see your fish more easily with the new layout. If you pull it off nicely you can really create a nice sense of depth, even in a 5 gallon tank.

Wisteria Difformis makes a great space filler plant. Cheap, easy to find and easy to care for. Just make sure to give it enough light.

Good luck!

I concur with the black background! Really makes everything 'pop'. I did it on both of my tanks, and it makes all the difference.

I'd tie some anubias nanas to the driftwood, along with a black background and a good cleaning.