There is not a lot you can do to encourage breeding and in all honesty would not recommend it until you are totally knowledgable about all aspects of keeping and breeding. it is very hard work with a high mortality rate, it is also very expensive and time consuming, i have bred them for several years and after the first time decided I had to be cruel to be kind and only remove a handfull of eggs from the tank for rearing and leave the rest for the parents. i know this sounds callous but believe me it is not. It is far worse struggling for hours a day trying to keep as many as possible alive to see them die 1 by 1.
Please think long and hard and do your research first, if you decide to breed when you understand all the pitfalls good luck and happy rearing.
1 last thing I found that by rearranging the tank and doing large water change so the water is colder acts as a stimulant. But not always.