Caramel Frappe said:
EDIT: Not mandatory, but forgot to mention this.
If you want a 30% chance increase at win-rates, I highly advise you install Curse [http://beta.cursevoice.com/games/league] and communicate with people. It was built for LoL, free, lag free and seriously helps people win more games because of talking about warnings, plans, and getting things done faster than typing things out which takes a lot of time. Pings can only take you so far when chatting on the mic gets more done.
Well, someone's shilling out for that...Haven't really had anything all that great come from using Curse, even back when it was broken when it first released and gave you enemy timers and camp respawn times. It was nice to have, but once you get high enough, people know what you mean by pings for the most part. And for new players...it's just sorta another distraction.
Personally, the biggest thing in MOBAs is just to be consistent and that decision making is something like 80% of the game, the rest just being mechanics. Though this percentage can change based on the character and how you're doing in the game. You don't climb or win by doing well, you climb and win by doing well at least 50% of the time.
Don't chase a kill too long when you've got a wave hitting their tower, chances are you can get it for free and that gives both gold for the entire team, and it makes the game that much easier to finish. Don't go for a neutral camp if you get more by grouping with your team. If you're getting screwed by range or just being outraded, stay back and just take the melee minions, and if possible, never let a cannon go by, as it nets you something like 2-and-a-half melees in gold.
But if anyone wants to get better at any particular game in the genre, pick three characters that exemplify the main mechanics of the game. Play Ezreal, Nunu, and I'd say Jayce for LoL. Ez for his skillshots and juggling act to use him perfectly with his passive for max dps while building minimal attack speed, Nunu for how simple it is to use him, and he sorta shifts through like four playstyles throughout most games, with jungle superiority early on(you're not going to kill him, his base defense stats are some of the most insane in the game in addition to being an early game terror due to his slow and attack speed debuff while having the exact same thing that instead buffs himself), to just being a fat tank that protects the backline and becomes a multiplier for his team's damage lategame, and Jayce for getting the idea of combos down in addition to learning more decision making(melee for mana here or just clear the wave with ranged E-Q?). Also all of these characters have been somewhat consistent throughout their existence, so there's not a huge chance of them being nerfed to their deaths anytime soon while also never being broken outside of sometime in 2012 for Ez and Jayce, and the start of this year with Nunu(but that was more due to itemization being broken on them at the time).
Also, most importantly, READ WHAT YOUR ABILITIES DO. And if it's your first time playing for I'd say at least a week, go with your gut and look at the character splashes, they'll probably give you an idea of what they do and you can probably sweep by with your gut telling you the Rule of Cool for you because you'll be put with either smurfs, which will go away after a bit, or other newbies.
As for other advice, just ignore and immediately mute someone that starts being a dick, it'll save alot of headaches, but don't get too personal about it, some people are abrasive because they wanna win and can be sorta assholish in giving good advice.