This probably isn't new news to anyone who's been battling Pandarian pet tamers for a while, but... Farmer Nishi is amazing for leveling up your low-/mid-level pets. You can take two low-level pets up against her; they just need enough health to survive up to about four castings of Sunlight.
Farmer Nishi has two elemental pets that mostly heal and have weak damage options: the Singing Sunflower, set up with Photosynthesis, Inspiring Song, and Sunlight, and the Terrible Turnip, set up with Leech Seed, Inspiring Song, and Sons of the Root (yep, she's cheating on her skill set ups). Her worm is a beast set up with Consume, Acidic Goo, and Burrow. I think he's supposed to be a silkworm, but his skill set is more like Mr. Grubbs.
The key to making this fight easy, I think, is an aquatic pet with a) a moderately strong, often available damage spell (the sunflower is going to heal ~200 hit points a round) and b) a self-heal, because you're going to need to keep it alive through all three of Nishi's pets. As you can see in the screenshot, I'm using Jubs, a Jungle Darter. Most frogs and toads have this same skill set. Other aquatic pets, or pets with aquatic abilities, may work just as well; aquatic is strong versus elemental, and the extra damage helps with the sunflower's healing.
Whatever pet you're using for killing things, you want to start with your low level pets, doing one ability with them before swapping them out to make sure they get credit for the battle. Neither the sunflower nor the turnip is likely to kill them, as long as they have about 500 hit points, and the worm will always go last.
Nishi will open with either the sunflower or the turnip, but usually the sunflower. If you get the turnip first, that's great; just kill it straight through. If you get the sunflower first and you're using a frog, you want to use Frog Kiss on it until you get it frogged; Nishi will then swap it out for the turnip. You're doing this because her worm has a very good chance of killing your pet if you take it on without the extra hit points from Sunlight.
The sunflower will open with Sunlight, then do nothing but heal itself until Sunlight is down to two on its counter, then cast it again. The turnip generally starts with Sons of the Root, which should give you an opportunity to heal yourself once before you can actually damage it. Sons of the Root is an eight round cooldown, so if you don't miss, you'll probably only see it once. It usually follows with Leech Seed, which is a four round cooldown, and then Inspiring Song, a three round cooldown. This means you will have rounds where the turnip does nothing.
If you've managed to get the sunflower second, either through chance or Frog Kiss, once the turnip is dead, you can kill the sunflower. At this point, if you're using the frog, you do not want to use Frog Kiss, since you're going to want to use it heavily on the worm, and you don't want to risk swapping the sunflower and the worm back and forth, because the sunflower will heal them both like mad. If Sunlight is going to run out soon, it may be worth passing to keep the sunflower alive long enough to cast it again; you want it for at least two or three rounds on the worm, if not longer.
The worm tends to open with Acidic Goo, then will Burrow and alternate Consume and Acidic Goo until Burrow is back up. If Burrow connects, it hits hard, easily 500 to 800 points, depending if it crits. Luckily it does miss often enough that it's not a guaranteed game-over. Spamming Frog Kiss and using Healing Wave on cooldown usually keeps a frog alive if it's got a couple rounds of Sunlight for extra hit points.
Depending how low level your pets were to start, you're usually looking at two to three levels when the battle's over.
If you don't have an aquatic pet with a heal yet, there are frogs, turtles, and water striders throughout Pandaria, which will start at level 22 or 23 depending where you catch them. Any of those should take you just a few tamer battles to max out, and they're plentiful if you want to farm for a rare one if you haven't got an aquatic stone.
