Looking at your collection, I'd suggest the following:
1. Focus on your initial team.
1.a. You've got a beast, a dragonkin and a mechanical. That's really the best set up to level first.
1.b. Catch your Core Hound Pup and Sunreaver Micro Sentry up to your Chrominus. Remember, pets don't get XP if they
don't participate in fights.
2. Hunt in zones with pets that are about the same level as your team. This way you fill out your pet list with new, higher
level pets, plus you advance the pets as fast as you can. Yes, you'll be moving around often, but it's more effective.
3. Once your initial team is 25, you can power level pets for beating the tamers.
Power leveling means putting a low level in for one hit, then swapping to the high level pet(s) to finish the fight. This
way the low level pets gets all the XP.
4. If needed, go hunt down specific pets to make your tamer teams more effective.
4.a. Get and level a Terrible Turnip
. This guy takes a lot of the pressure off hunting for capture since Weakening Blow
won't kill a pet unless it's got some kind of self damaging move.
Once you've got a set of teams that can beat the dailies, the pressure is off. When you can beat the tamers, it's a short step to farming them for XP. And you can hunt for any pets you want to fill out your collection with adorable sidekicks.
Also, once you're at the power leveling stage, and don't have a lot of bandages, there's a few spots that are nice if you also want to work on specific types of stones.
Krasarang Wilds - Lots of high level beasts, some flying. Horde can hunt around Thunder Cleft, Alliance can hunt around The Incursion. Both spots have easy access to stable masters for pet heals if you don't have a lot of bandages
Valley of the Four Winds - Critters critters everywhere. Hunting around Halfhill there's easy access to a stable master.
Vale of Eternal Blossoms - Lots of high level aquatics. Not as easy access to a stable master.
Mount Hyjal - Where you first zone in there's a stable master, and lots of critters, flying and the occasional magic. But the pets here are only 21-23 rather than 23-25.