Start with unrefined coconut oil. It'll be a solid in the tub, but will quickly melt in your hand.
After your shower at night, take between a teaspoon and a tablespoon-sized glob in your fingers, depending on the length of your hair.
Work quickly to massage it through your hair. You'll want to make sure you've covered all the way from your roots to your ends. Use extra oil, if needed.
Find a way to pull your hair up and back so it's not flopping around.
Sleep with your hair this way (use a shower cap, if you are worried about greasing up your pillowcase).
In the morning, wash and condition your hair as usual. When your hair dries, it'll be super silky, shiny, and soft! For me, it lasts about a week in turbo hair mode and then starts to wear off.
Depending on your particular hair type, repeat every week to two weeks, as needed.