How to REPORT properly
Although I'm aware that some (maybe all) of You may downvote this post, things won't change if nobody acts. Someone has to say it. Clearly and out loud. This game has become so popular in the last 2 years that almost everyone is obsessed with it's complexity, plays it with friends frequently or at least has an existing account in one or more regions. The growing player database involved an even more gaming community and it's almost impossible to set up age or intelligence limits. Most of the >>Greatest Summoners<< are kids (between 8-16) in the real world and most of them (again) are toxic as hell.
Long story short: You are most likely to be reported by me if You:
- don't say anything in champ select but refuse to take the remaining roles
- instalock Your champion assuming others will accept Your choice just because You were "louder" or "first"
- leave the game with a quick (rage) message
- write down more lines during the game than the entire game's length (in minutes) divided by 2
- say anything in team/all chat besides useful advice, information about champions/situations (buff timers etc) or granting them Your best wishes (nope, "uninstall LOL" doesn't count as a noticeable advice)
- write down one of the following words in all chat: "izi", "easy", "ez", "noob", "nob", "nub", "n00b"
- spam /surrender every 3 minutes after a previously failed one
- refuse to leave your lane during the first 20-25 minutes of the game (also missing teamfights - even if Your team is losing 4v5 or starting to fall behind)
- build 2 or more lifesteal items on meele champions
- start the game with 50+ AP (regardless the role You play)
- finish the game with 300+ AP as support
- refuse to buy sightstone and/or the wards placed by You is nowhere near to 15-20/game as support (calculating with average game length [30-35 minutes])
- consider to buy GA on a tank or naturally tanky champion (especially Volibear/Sion)
- survive a gamechanging teamfight with full HP
- plays in general the following champions:
Bot:
maybe 
Mid:

Top:

Jungle:

(Last one is a joke - but I must say toxicity is usually paired up with mobility. The more moblie a given champion is the more ignorative/retard the Summoner who uses him/her/it) - also Ekko still doesn't count as a "high risk high reward" champion. KAPPA.
? Is the Sky Blue?
are all examples of champions that need lots of AP to be effective late game. Sona late game with 600+AP is OP with her shields/buffs and attacks which is all she does for instance.
on a tank makes them more tanky because when alive again they are harder to kill
combo (they just shouldn't build them high priority anymore) so you want them to die