CREATE AN ACCOUNT AND INTERACT WITH THE COMMUNITY!
LoL has a thriving online community spread throughout the world. You can look at the Boards (http://boards.na.leagueoflegends.com/), browse /r/leagueoflegends, read game wikis, and much more!
DO: PLAY THE TUTORIAL. DON'T: TYPE ANGRILY AT OTHER PEOPLE.
Riot Games - the developer of League of Legends - has implemented a decent tutorial system, however the best way to learn the game is to play it. And when you do, always remember: #NoReasonToRage
EXPERIMENT WITH DIFFERENT ROLES AND CHAMPIONS.
Your first 10 or so account levels in League of Legends will allow you to adjust to many of the nuances of the game. Try a variety of champions and positions to see what works for you!
GET THE HOTTEST INSIGHTS AND LEAGUE KNOWLEDGE.
There are tons of resources out there for you to fill an eSports digest: Surrender@20 covers League of Legends news and patches while resources like LoLKing can show you pro Champion guides!
LEARN FROM THE PROS.
Many professional eSports players stream gameplay videos and tips & tricks. LoL Academy and /r/SummonerSchool are great resources for finding ways to improve your game.
FOCUS, IMPROVE, AND COLLABORATE.
The League of Legends community contains a wide variety of fans, enthusiasts, and players. Work with new friends to help you improve what you are great at! You can always improve in League.
YOU'RE DOING IT!
Now get out there on the Rift and show everyone what you're made of, Summoner!