When dealing with livebearers there is really nothing you have to do to encourage breeding. All that is needed is good clean water, steady temp, fed well (not too much lol) and they will do their own thing. With livebearers the best advice I can give is always have a plan with what to do with the fry. Its not a question of will they breed but when and how many.
Female livebearers can inseminate themselves up to three times even without a male present after the initial fertilization. It is also recommended to have 2F/1M that way the male doesn't stress the one female out by attempting to breed often. Have fun, watching livebearers give birth is an exciting thing to see. Happy fishkeeping!