One of the easiest way to make your hair grow fast is by brushing 100 times a day. Yes, I say 100 times a day; from the scalp to the tip of your hair.
Apply your comb or brush to your hair gently. It should be from the scalp because it's also a way to massage your head that triggers the hair to grow.
I always do this everyday. No chemicals used, you just need an effort and time to do this.