My initial plan (before I ended up with all males) was to keep one male and two females in a 33 long with dividers. Male in the middle section, females to the sides. I was going to feed them up and grow them for a long time separately - making sure the females were very fat and healthy - and then try introducing them into the same sections of the tank for short periods. I figured that if conditions and feeding were right, mature females may become gravid, especially in the presence (i.e. shared water... visual contact...) of a male.
If this approach failed - I would have played around more with water parameters and feeding - and made sure to provide ample spawning vegetation... I believe they require big patches of fine textured plants to spawn in... java moss is a good bet. I'd also try moving out all other species in the tank.
Just some thoughts.
- Sam