To be honest, I never did anything special to keep my hair smooth. I've never really been bothered with split ends because I cut my hair a few CM every second/third month. People often ask me how I keep my hair so smooth while it's so long (~1 meter), but I don't really have any tips besides my regular routine.
When showering, I shampoo it twice and use a conditioner after. I don't really leave any of it in my hair while showering, I wash it out right after massaging it in. I think my hair has remained so soft and shiny because I wear a ponytail quite often (hair in your face and in the way sucks). On top of that, I never use hairspray or other products. :v
People have different hair though, some are addicted to special creams and other expensive stuff to keep their hair intact. I do believe that not using hairspray has helped me a bit, but I wouldn't give it too much credit.