Sexing all livebearers is dead easy as the males have a gonopodium; that's a rod like structure formed from the anal fin (the one in front of the tail, on the belly of the fish). Females have a normal, fan shaped fin.
As for getting them to breed...make sure you keep them wet? The fry are pretty big and don't need any special food. They'll either find enough in the tank (especially if you have live plants) or, for best growth, grind up a good quality flake.
If you want to breed some kind of special colour or tail shape, ah, then that's a whole different ball game, and you'll need lots of tanks for keeping males and females separate and for growing on fry.