Your sleeping environment
Use comfortable bedding. Uncomfortable bedding can prevent good sleep. Evaluate whether or not this is a source of your problem, and make appropriate changes.
Find a comfortable temperature setting for sleeping and keep the room well ventilated. If your bedroom is too cold or too hot, it can keep you awake. A cool (not cold) bedroom is often the most conducive to sleep.
Block out all distracting noise, and eliminate as much light as possible.
Reserve the bed for sleep and sex. Don't use the bed as an office, workroom or recreation room. Let your body "know" that the bed is associated with sleeping.