With Pet Battles enabled with the most recent patch, I found a few exploits:
1) By logging into the same account (which seems to be intended) you can use the ability "Revive Battle Pets" to heal all your pets which are shared across characters but doesn't share a cooldown. This makes it easy to heal them if you're fighting a lot. You can also just switch characters instead of dual box if you have a slower computer. The ability is locked out and gray but if you click it it still works and then goes on its proper cooldown. Does not heal pets you're in combat with. Additionally, you can log an alt at the stable master and just alt tab and heal.
2) In Stonetalon Mountains, you have to fight the trainer Zonya the Sadist. She has 3 level 7 pets and you can repeatedly fight her as the quest won't "complete". This is great experience up to 10 or so.
3) If you capture a wild pet, and use an aoe ability that hits all enemies (eg, Lil Targ's Arcane Explosion) you can kill it and capture it which gives you both the pet and the experience.