What is the best way to get perfect nap?

You need a dark room, cool temperature (66-70 degrees F), quiet and it helps if you can clear your mind of concerns/worries. Naps are most effective if they are short (less than 30 minutes) if you sleep longer, then you start cycling into deeper planes of sleep and if awakened you will not feel well rested.

Keep naps short. Aim to nap for only 10 to 20 minutes. Take naps in the early afternoon. Napping after 3 p.m. can interfere with nighttime sleep. Create a restful environment. Nap in a quiet, dark place with a comfortable room temperature and few distractions. After napping, give yourself time to wake up before resuming activities — particularly those that require a quick or sharp response.