- when picking a jungler, you need to take things into account. First is the enemy jungler. Are they a good counter-jungler? If so, you might want to pick a champion that's more resistant to that kind of thing. Udyr, trundle, lee sin, warwick are all strong junglers that can do whatever the hell they want when they get counter jungled. Bad champions to pick are amumu or fiddlesticks.
Second is your lane compositions. Does your team have a champion that is very strong late game, but probably won't win their lane matchup? In this case, don't pick junglers that can't early game gank, or champions that can't gank frequently (level 2, 3, or 4 are all early ganks). Good champions to pick are nunu, lee sin, nocturne, shaco, fiddlesticks, rammus and anyone else who has a quick clear time on blue route and decent ganking potential at level 4. Bad picks are master yi, warwick, and to an extent gangplank and try…
This isn't necessarily about jungle routes, but just things to note while jungling: