What is the best way to stay at a comfortable temperature when i sleep?

Depends: Typically it is easier to fall asleep in cooler environments than warmer environments. As we enter rem sleep our ability to regulate our internal body temperature ceases. So a consistent temperature in the room, not too cold or warm, is preferable. Moreover, if you are prone to night sweats, having light, loose fitting pajamas, rather than tight, thick clothing may not be the best.