Like all plants, Amaryllis needs light, water, fertilizer, the correct temperature range, and a good potting mix in which to grow. Amaryllis bulbs and tend to have a more seasonal growth pattern in northern climes. All you have to do is be aware at which seasonal stage of growth your amaryllis is at, and provide it with the right care for that stage.

 For convenience, let's split up the Amaryllis growing cycle into three stages:

STAGE 1: BULB STARTS GROWTH
This is when buds and leaves first emerge from a "dormant" bulb (late winter-Spring) and the plant is going to bloom

STAGE 2: BULB IS GROWING
This is when the plant has finished blooming and is now in full leaf (late Spring through Fall) requiring maintenance care.

STAGE 3: BULB IS "RESTING"
This is when the bulb enters a period of reduced growth or an "enforced" dormancy and is preparing to repeat its bloming cycle (late fall through winter) 

Plants that have been forced into dormancy  to bloom for the holidays may take a growth cycle or two before the adjust to the above schedule.