Ok, listen to me:
a) Be sure that you want to win. This is the most basic stuff you need. Do not join ranked if you do not seriously plan on fucking destroying the enemy and having a blast doing it.
b) Be kind to teammates. Being a psychologist in real life has helped me immensely in ranked lol games. When we usually win the match, my teammates praise me for keeping the team together. Try to do the same. Lie if you have to. People are full of insecurity and cannot blame themselves. Even I, when ganked by a jungler, will yell 'WHERE IS THE FUCKING MISS' in my team while I know that I was stupid enough to overextend and cause my death via a gank. After having many games in ranked you will understand how important not swearing in teamchat is.
These 2 are the only things you need. Other than these 2, focus on mastering 1 or 2 roles in the game (like mid & jungle for instance), do your research in lol wiki etc. and prepare to lose. Losing is part of the game, and it just means that you have to learn more. Ignore the brats who yell at you (thus keeping the teamchat clean) and keep playing and enjoying yourself. If you feel that you do not get enjoyment, immediately stop.