For tankmates you should get some more cory cats to start. They like being in groups. The bigger the gang the better. You could also get a pearl gourami, a bushy nose Pleco, and a couple swordtails.
As for aquascaping, I am a fan of the natural look. Brown/black sand or gravel, driftwood, and a couple rock "formations".
Do you want live plants? If so, what kind of light do you have? And do you plan on getting co2 and fertilizers and all that jazz?