Hey, what's up!
Here I come with some basic things that will help you a lot when playing (most of the people will know this stuff, but for the guys that doesn't.. also is good to remember it ;D)
1. Always be patient. If you are in a game where "kids" are trying to provoke you, just ignore them or mute them. If you are the type of person that gets distracted or mad with the least commentary, Ignore/mute all the players when playing. Maybe some will say: Hey, if you do that your not communicating with the team, etc etc. But pings are for something, am I right? Chatting is not the only way to communicate with the team mates. That's why the mute and ping exists.
2. Always be positive. This sounds ridiculous, but the fact is, the emotions are involved on what ever we do. If you had a bad day, and you are angry/mad/tired or what ever reason that can affect you playing .Try not to play. Just relax and try other day.
3. Never blame other players. Always think what you can do to get better. Yes. I know there is some games where there is an allie that goes 0/10 but think as if you were that guy. How would you feel if they blame/insult you? What you can do on those situations is to try to give him/her tips or try to make him feel not useless. Otherwise if you insult/blame is not gonna get you anywhere.
4. Team work. This game is all about team work. If you think you can play alone, and carry all if you get all the kills, you are playing the wrong game... Think about it. If everyone does what ever they want, and don't focus on the objectives, what's the point?
Who do you think will win, Team A: top lane split push, mid and bot pushing mid, while jungle farming,and never grouping? or Team B: Always sticking together, going for the objectives?

Hope you guys enjoyed reading my first blog, and had remembered or "learned" something new. Also Thanks for taking your time reading this blog. ;)