1. Set an alarm, and only sleep 20 to 25 minutes. That's the perfect amount of time. If you sleep longer than that, you'll slip into a deep sleep and wake up feeling groggy.
2. Nap at the same time each day. Early is better, so it won't keep you up at night.
3. Shut the blinds and turn off the lights.
4. Take a nap in an actual bed if possible.
More tips at Time.com
Photo courtesy of bengarrison