One of the tricks of the trade is using rubbing alcohol as a growth retardant to keep the stems shorter and stockier. Add 2 tablespoons of it to a gallon of water and use that each time you water them. Forced Narcissus do not need any fertilizer. When they are done, thank them and discard them. They can't be rebloomed.
Amaryllis are another story entirely.
With care, an amaryllis can become a family heirloom, rebloomed each season and lovingly made a part of your holiday traditions. The new choices here are the wide range of colors and sizes available. The holiday amaryllis is actually in the genus Hippeastrum and comes from South America. The Dutch and South African hybrids have extremely large flowers, 8-10 inches across. The flowers may be single or double and range in color from deep, velvety red through fire-engine red to orange, salmon, pink, white and blends of these.