Okay so, we’re in the jungle now and you’re probably wondering where on earth the jungler is supposed to ward? I mean you’re going everywhere you can’t possibly have everything warded. True. So instead of giving you a map and telling you locations X and Y should be warded for reason Z I’m going to help you think through the logic of where you should be warding and why.
If you want to invade the other side’s jungle think about where you want to head first. Many junglers start blue. If that is the case do you want to try to contest blue with your team? Or try to kill them at their red? Maybe you just want to smite steal and not even fight. All of these decisions have to be thought over first. Only after those decisions are made do you decide where to ward. First of all if you’re just going for a buff steal and not a fight you need to make sure you get to the opposing buff that the enemy started before they get there. This means place a ward down at that buff or on the bush that is the entrance to their wraith/ wolves camp(depending on if you’re going for red/blue). If you’re trying to steal or fight the jungler it’s not a terrible idea to make sure the correct tri-bush is warded so you have knowledge of what either the top or bot lane is doing.
If you’re going to gank a lane before getting your second buff make sure your buff is warded(please).
I generally like to carry a sweeper rather than a warding trinket on my jungler to clear wards and set up ganks. Keep in mind there is another jungler though, so he’s going to want to counter gank you, and gank in general. Try helping out laners ward and keeping control of that bottom tri bush. Knowledge of where the other jungler is can only benefit you.