Ok ill start first with what i've learned from my few relationships which all of them broke my heart
1. Believe in yourself and ESPECIALLY what you say even if it is a lie.
2. Dont be very nice to them. Dont give them anything easy.
3. Its not profitable to tell them sweet romantic drama things actions speak louder than words.If she cant understand she better commit suicide.
4. NEVER EVER EVER EVRER EVER EVER NEVER EVRER X 100 000 000 000 CHASE A GIRL NEVER NEVER THEY GOTTA BE CHASING.THIS IS FROM NOW MY PLATINIUM RULE.
5. Dont take them as a grant from time to time do something to show them that u care.
6. Girls who drinks alot and use drugs are good only for few sex sessions but not for relationship
7. Do not let her know everything about you.There must be always some kind of mystery about your personality
8. Never be needy or clingy
9. Always think about yourslef at a frist place.Call it egoism as u wish
10. Give them space
I cant think about more but for sure there are but at the moment i cant think of