League of Legends is probably the most infamous games to train for. To put it simply, it is a team based game. Unlike Star Craft and other multi-player games you have to rely on your team to know what their role is and to play it well. Sometimes you can play perfectly and your team will loose. Treat it like a learning experience and try to make sure that your team gets what it needs to win. Bellow is some methods I learned to gain more success in the ranked ques.
Find one character you like and try out these tips
1) Know your role
As a new LOL player I always wanted to kill everything. So I made sure to buy tons of attack damage for Gragus and play anywhere I wanted. Obviously that was really really dumb of me because Gragus is a caster, and most of his moves scale with attack damage of AD, second it really killed my team composition that I was not where I needed to be.
The basic roles are Caster, Tank, support, AD carry, and Jungler. (obviously, the higher ELO you get the less standard things become.)
Caster: magic damage
Tank: harasses the enemy team while protecting AD carry(s) from incoming attack
Support:generally heals and harasses enemy team, and lets the AD carry kill all of the minions
AD carry: does most of the physical damage
Jungler: assassin that gets gold from jungle and then attacks the enemy team
As for lanes, there is nothing set in stone for what you should do but it is standard to put your caster mid solo, AD carry and support bot, and then another AD carry or a sustaining Tank top.
This is a very gross and small summery of roles and I highly recommend that you look it up on the internet. (because it is always changing)
2) Last Hits
Gold is a huge concept of this game, you need it for everything.
Last hitting does separate the veterans of LOL from the newbies of LOL, because it allows you to take control of how your lane is going to be moving.
Last hitting is when you wait to attack a minion until their life is low enough to kill. Efficient way to kill them. It allows you to save your attacks for other things like enemy champions. The big thing is that if you do it right your minions do not push your lane and you can constantly farm
Typically you do not want to have to push the lanes to get minion kills because it leaves you open for ganks and makes it easier for your enemy champions to move under the cover of their tower taking them out of attack range.
Killing towers can provide a lot of gold. However, it effectively makes harder to stop your lane from pushing to far and farming.
In LOL if you can control the minions you can effectively control the economy of the game.
Sometimes I purposely let two enemy minions die to my ally minions to keep the their minions on my side of the river and make the enemy champions have to come to me for gold.
3) Skill shots
You need to master your champion's skills and summoner abilities.
Riot has done the painstakingly task of making characters that are very unique. Each character has different abilities and the more you are able to take advantage of them the better off you will be in a game.
Usually this take s some time to just play around and let your mind absorb the information. Soon you will be coming up with combos that did not exist or at least the didn't in your head.
Like what I call the Gragus "double ult", where you *accidentally* placed your barrel to far behind your target and now they are moving forwards and going "yess! that fool cannot aim" and then I unload my ult into their face and throw em into the barrel dealing copious amounts of damage. Unnecessary? yes. Waist of an Ult? maybe. Takes skill to do? HELL YES!!!
Just make sure you can use your abilities to the maximum that you can possibly think that they could ever be used. Because sometime people expect that from you.
Hopefully this helps some new people get their feet wet and kick some @$$!