In addition to what WildBetta has said, try to pick up a piece of driftwood. Soak it for two days so some of the tannins are out of the equation, and then place it in the tank. More tannins will stain the water a bit of a tea color, but this is beneficial for these fish. You soak it for a few days first so that the water is clear enough for you to check on your fish. You can also get Indian Almond Leaves for the same effect.
Some people like to get ping long balls as toys for their betta fish as thy are naturally inquisitive. If you do this, make sure the ball is clean (wash in a white vinegar/water solution at 1:10 parts) and be sure that there is no chance of the fish getting lodged under the ball in a tight space.
Check everything for sharp edges. A betta's fins are exceedingly fragile. And, as I found out the hard way, always be sure there is a guard on your filter intake.
Aside from that, betta fish are really easy and fun to keep.