Read this site over a few times, just to get an idea of the equipment you will need;
http://webrbiz.com/angelfish/amh.html A small angel spawn is 200 fry, each needing 1/2 gallon of water to get to a minimum selling size. Large spawns exceed 600. I've been breeding angels for years, the hardest part is finding someone to buy your fish. Once you get a system down breeding them is easy. I sell mostly to brokers, a few shops, and at auctions. Make sure to have plenty of extra tank space, if the market slows down you won't be selling any fish for a few months, and have to house them until it picks up.