Always prepare your naps in the following way.

1. Have water and maybe something sweet nearby to help wake you up.
2. Have a timer on so you do not sleep too long.
3. Have a pillow or something allowing you to sit up a little bit afterwards.

Then just schedule some time after your timer goes off where you just ease into the pain of being sentient again. It is also possible to drink coffee before you nap, since the effects of caffeine will not kick in before after you wake up. Regarding the first point it is also really sweet (pun intended) to put say a small piece of chocolate on your tongue and just sit up and close your eyes.

Lastly, you just have to learn what works for you. Falling asleep is also not mandatory for resting well!