Place the plant a warm location that gets a lot of sunlight. Frangipani are used to tropical climates where the weather is warm and the sun is plentiful. However, frangipani do not handle cold weather or frost well. So if you are growing them in a location where the winters are cold, move the plant into a warm location, like a greenhouse, in late autumn.
Use a sandy soil that drains well. Frangipani plants don't do well in thick, clay soils. The plant can thrive even in less nutrient soils but not in those which are too thick and can't drain.
Let the rain handle the watering. Again, as a tropical plant frangipani trees are used to receiving frequent but brief rain showers. Over watering may cause the plant to rot. If the plant is located in a particularly dry location it may be necessary to water them. Butt in most environments, the plant benefits most from the rain.
Water once a month in particularly dry locations, by giving the plants a deep soaking. Again, don't over water the plant, but provide just enough water to make up for what is lost due to lack of rain.
Do not use fertilizer as most frangipani plants don't need it. If the plant has real troubles add a little bit of fertilizing and see how the plant reacts. Even if fertilizer is necessary, use it sparingly.