The male and female should be able to see each other for a few hours a day. It will motivate the male to make his bubblenest and the female to develop her eggs. You can keep the tanks right next to each other and use some dark paper as a divider until their appointed times for seeing each other.
Look for longer fins. The female is the carrier for the gene that determines fin length. Also, look for colors that could potentially be vivid. Most bettas from stores are poorly cared for, so keep that in mind when you purchase them. They WILL be prettier after a few weeks of quality care.
You should ready the female for a month before breeding. Condition with high-quality protein-rich foods.
Seeing the male will stimulate the female into producing eghs. She will have VERTICAL (up and down) stripes when she's ready, NOT horizontal. Also make sure her ovipositor is clearly visible before breeding.
Anything else?
