Your ability to wake up early is heavily influenced by the quality of your sleep. Freshen the air in your room before you go to sleep (or just sleep with the windows open if the temperature outside allows you to do so), and you will have more relaxed and more deep sleep. In addition to that, this will also help you fall asleep faster!
It’s vital to understand that having a deep, relaxing sleep is the first step for waking up early. Sometimes, you’ll sleep for 10 hours straight, yet you’ll feel drowsy in the morning. There may be many reasons for that, and stale or stuffy air could be one of them.
So, open your windows, get more fresh air in the room, and enjoy the sleeping! If you live in a place where you prefer not to open your windows (busy smoggy street, noisy neighborhood or if the air outside just does not feel fresh), get an air freshener and a revitalizer. You will see the difference once you wake up refreshed, and then continue to feel energetic all day.