They need excellent drainage and need to be kept moist but not soggy. Mine are in a mix of Cactus soil and perlite. Fertilize every other week during the spring and summer and taper off in early fall. Use a high phosphate fertilizer such as 10-54-10. Regardless of what you use, make sure it's the middle number that's high as that will help encourage stronger blooming.

I have a few frangipanis in pots and they havent flowered at all this summer. I may not have fertilized enough so will try high phosphate next spring. Hope you have success with yours