1. Try to keep temp steady around 82F
2. At the moment, isolate them for a few days - don't let them see other fish.
3. After the isolation period, do not let the pair constantly see each other. Only flare them daily for 5-15 minutes. If possible use other fish as sparring partner - male to male and female to female. Once they are aggressive then flare the pair to each other.
4. Check water pram.
5. Keep feeding nutritious foods 2-3 times daily.
6. Most important, be patient :)
Note: I do not rely on nest nor breeding bars on females to breed. I rely on flirting behavior. If both show flirting behavior, I breed them.