Alright, so this might sound dumb, but you really shouldn't need any potions. Start off with your q on red-side, no matter what team you spawn on, this means that you'll be smiting the golems or whatever they're called now. At level 2, get your ice field, and your sustain will be absolutely ridiculous. Don't use your q every time it's up, wait for the damage buff to wear off, and you won't even have mana problems.
Now here's where you might think I'm really trolling you, but I'm not. If you have someone mid that can REALLY benefit from a blue (Talon or Syndra), GIVE THEM YOUR FIRST BLUE. You don't need it, and you should still get enough EXP to get level 3.
If you run into anyone trying to counter jungle you, be sure to fight on your ice field, you'll have the sustain thanks to the life steal in your runes and masteries. I've outdueled a Vi, Fiddle*****, and Master Yi. Remember that Trundle's pillar can knock enemies up slightly and disrupt their spells.

Take the lower scuttler as soon as you have an opportunity and every time after (watch your mini map), farm up to get your stalkers blade, because once you have that under your belt, you can gank just about anyone and ruin their day. Trundle doesn't have many weaknesses, but do your best to shut down the enemy adc, and don't feed them. Anyone top that is a hard dueler (Fiora, Irelia, Riven) can get wrecked by your ganks. Just wait for them to push out a bit, and come in behind them, you take away some of their AD with your chomp, and block them from running away with a pillar under their feet. Don't hesitate to drop your ice field to catch up and make sure that your pillar doesn't push them away. Ganks mid lane can be a bit tough, but counter ganks are where Trundle truly shines. Let's say a J4/Xin gets a bit too happy and comes flying in hard at your mid, you can come in, chomp him and then make sure the enemy mid laner stays away with your pillar, and increased chasing potential thanks to your ice field. Now if you get a kill or just manage to save a life, you HAVE to spam your dance.

This can be a bit of a tricky situation since Trundle doesn't have a hard engage and CC, so the best bet is to rely on either your top laner to engage or to bait a team fight at Baron. Trundle excels at team fights in jungle with his pillar. It can almost completely block of an enemy from the fight and turn 5v5s into your teams favor by making them 5v4 or 5v3. Do your best to isolate the enemy adc with a pillar, flash onto them if you must, drop your ice field and chomp their face repeatedly until they succumb to your life steal. Don't forget to use any item actives that you may have. A hydra/bork/randuins active could be the difference between getting kited and coming out as the victor.