Raising the lamp a few inches a week should be about right. Measuring of the ambient air temperature under infrared lamps is not a direct measurement of the heat that the chicks will feel. Watch the chicks' reactions and adjust the height of the lamp. Some people cover litter for the first few days of brooding. If you do, use rough, crinkled paper.
Smooth paper causes chicks to slip and develop spraddled legs.
Molds will develop if paper is left on the litter more than three or four days. Remove guard after seven days. Keep litter as dry as possible. Whenever necessary, stir the litter to keep it from packing. Move feeders and waterers to new locations to help prevent the development of wet areas.