Communication, understanding, unconditional love for the other person (meaning you love them for who they are and don't try to change them). There's much more.
How old are you?

Good advice from awayandalone.
Trust and discipline too. Never manipulate them in any way. Never hit them, or hurt them with your words.
Keep the love alive by going out of your way to prove that you love them. By sending gifts etc.
And are you a boy or girl?

You are right in what you say and I have followed that advice to the best of my knowledge, but I still haven't been able to find that special someone in my life, I guess you are also right in that "there is much more"...