His Q is perfect for counter-counter jungling, if you can land the E in the correct place and get one basic attack with Red buff then double up with your Q you can shut down most champs in early ganks.

Once you have Wriggles, boots and Frozen Mallet you can follow anyone. Get Aegis if you are going initiator/tank for team, Trundle isnt a full tank, but can become one with his Ult, however it is useful to have an Irelia or Udyr on the team also who are tanky and have lots of CC.

Little tip place his E in front of where someone is running, so it pushes them back. Also wait for a flash to occur before placing the E, otherwise you will miss.

Team fights with minions around grants a lot of sustain for Trundle with his passive, and smite also will proc his passive.

(Will extend guide when i have time)