What are some safety precautions I should take for my four to six month old child at home?

Safety. Way too much for 400 letters! Try: http://www.babycenter.com/0_childproofing-around-the-house_460.bc. Safety and health concerns should also be discussed at your well child visits. .
Be cautious. Your baby can fall off a changing table or bed. Always keep a hand on the infant if you turn away. Pacifiers can be pinned to a garment but should never be worn like a necklace. Any small object within reach will go into baby's mouth. Avoid small toys or toys with small pieces that may break off and become lodged in the throat or lungs.