This is my story on what it takes to be a good Jungler. It is also why Jungling is too hard and I'll never be good at it cos all I do is try to gank over extended lanes that are warded where I am
Jungling in league is basically playing a 4 position (that is, in general terms, you will be the 4th richest person on the team) that requires you to have global map presence while your opponent can do the same to you
You have to gank 3x more than doto mids
However, jungle farm is always available so you are sacrificing farm for gank opportunity. You are also sacrificing the opportunity to gank other lanes. Its basically a huge balancing act of the most important resource - your time. so you better not Fuck up
-Because of this it's important to know where all the wards are which requires good team mates or being able to guess the position by player behaviour as you come for ganks
-Also, the good opposing Junglers can either guess or see you coming for gank and either counter gank and fuck you up or going into your jungle and stealing your shit
-Its important to understand which lane is more gank able than others which requires you to not able to be able to read the lane, but to understand lane match ups ie. At level 6 riven is likely to go all in on singed or that garen counters akali so is likely to be aggressive at level 3. You abuse that and gank their asses.
-It is also important to know ganging which lane is key to your victory. You basically have control over the effectiveness of your team going into the mid game. Do you want to cripple the core player of their AoE comp (Orianna), or do you want to make your poker much stronger (jayce). Do you want your tf to dominate the map in midgame and gank for him. Or Do you recognise that no matter how much you gank a lane they will always be useful to their comp (malphite). Or do you know that if zed gets ahead of his opponent it will snowball out of control.
-You also have to play invisible mind games against the enemy Junglers that requires you to have knowledge of his path, what lanes he is valuing, his last position and which lanes are potential gank targets, which is why consistent counter gankers like diamondprox are pretty amazing. Counter ganking is incredibly powerful because gankers tend to overcommit and use some skills to initiate. And as such you need to be wary of this too. You also have the choice to punish bad gangs by your opponent by stealing his camps, especially if he is a poor farming champion.
Beyond all that, there's the generic requirements such as what kind of Jungler are you playing - farmer, counter Jungler(specialises in making life hell for enemy jungler), counter ganker, power ganker (my category for those with powerful ganks), early game ganker (those that depend on getting early game gangs off) and map presence gankers (high mobility)
Also, you need to know the different gank paths and which ones are the best for the target position and the way your champion ganks
There's the mechanical requirements of your Junglers like aiming their skillshots and positioning. And playing dangerous smite games with the enemy Jungler
Tl;Dr Jungling is hard. Respect your junglers
