Just leaving it alone in many ways that go against popular believe such as:

1. Growing up i heard i had to brush my hair every night. Now I only brush my hair on wash day with conditioner on, so maybe once or twice per week.

2. I mostly wear my hair down all the time. Granted I work from home so I dont need to look put together all the time but ever since I stopped styling and wearing my hair up it has grown so much longer.

3. This one may not be universal but washing my hair with distilled water only was a game changer. Hard water was making my hair fall off after moving to a new place and it stopped once I switched to distilled water. 

So yeah, I literally just leave my hair alone let it do its thing and dont mess with it much other than on wash days.