Dua before sleeping and protection from nightmares etc.

• It is Sunnah to join both hands, read the last three Surahs of the Qu’ran (Qul-Huwallah, Qul-A’udhu Bi Rabbil Falaq, Qul-A’udhu Bi Rabbin Nas) then blow on both hands and wipe the hands all over the body (starting from the face and front of the body). This should be done thrice. (Bukhari)
• Ayatul Kusri should also be read. (Bukhari)

Then Recite:

Allâhumma bismika amütu wa ahya.

O Allah, with Your name I die and live. (Bukhari)