Not Updated For Current Season
This is a jungle poppy guide. It pretty much counters any team you face and it only gets stronger the later in game you get.
I run attack speed reds and life steal quints for the boost to early game sustain. The one movement speed quint. may not seem like much, but it really helps when it comes to securing ganks. As for my yellows I run the obvious flat armors because it helps as any jungler. For my blues I go with 6 scaling cool down reduction due to the fact that her W gives good MR and the the cool down reduction helps with spamming abilities, as for the three scaling magic resist I just like the boost of survival.
As for items, you want to primarily go for a tanky build. That being said I don't mean sacrifice all damage, so look for items split with health and damage such as titanic hydra and black cleaver, these two items are very strong on poppy creating more of a bruiser than a straight tank. You'll be plenty tanky as is with your W's passive and the armor/Magic resist you build later on (via dead man's plate/ maw or mal.)
In any scenario it's not bad to use your Q and your passive's ranged auto as harassment. When it comes down to it you want to be looking for any chance to get your E's stun off, provides you land your E's stun it's very easy to dish out quick damage using your Q. If it helps you land a good E i suggest using your chilling smite and your W's active to boost mobility and angle yourself into crashing them into a wall. If someone gets caught out and you have allies nearby it becomes very easy to pick them off and go into a 5v4 team fight.
Over all I'd say this build is very strong. It provides you with good mobility to make landing E's with ease, and it provides you with enough bruiser capability to stick around in a team fight for quite some time and dish out damage, CC etc.
Creeping / Jungling
When it comes to jungling I always start with the same two routes. Depending on what side you start on you'll begin with gromp or golems, if you begin on red team than you'll want to go gromp, if you start on blue side you'll start on golems. Reason being you want the strongest leash possible (via bottom lane). I prefer to smite immediately giving you a boost to damage via gromps poison or boost to sustain via golems on hit stun affect. After you clear gromp/golem you want to rush your blue/red buff. While you're clearing gromp/golem and red/blue be sure to be picking up the buckler from your passive for stronger sustain. After you clear your buff you want to go to the nearest scuddler and kill it without using your smite since it gives back more health from your life steal and killing it in general. Once you've successfully killed the scuddler you must go and kill either wraith camp or wolfs depending on what side you started (wraiths if you killed red first, wolfs if you killed blue first) after this you're ready for your first back.