This is not meant to be a full guide, and it's mostly a copy?paste from a comment I made when I first played the game, with added info. These are just some tips I've noticed:
1: The Geonosis one is locked until you complete the Utapau one.
2: Gonks can die, and they don't respawn. If one dies, you have to go back to start. In terms of fighting, the Catonica one gave me the most trouble. The Gonk there died twice, and it was the only Gonk to die during my run.
3: There is no such thing as friendly fire. If you see the Gonk being attacked, feel free to go nuts. For the Cantonica one, I recommend General Grievous. The enemies seem to go right after the Gonk Droid. Grievous has 4 lightsabers (for the enemies that use melee on the Gonk), a gun (for the enemies that sit back), and grenades. Just stick to the Gonk, and you'll be fine.
4: The one at Kef Bir was annoying af. While there are no battles, I'm not good at platforming.
5: Don't worry about the Gonk's health. Other than the last mission, it recovers its health in full after every battle.
6: The Final Gonk isn't too bad. You get three battles, and while the third one is the hardest of the three, the Gonk only lost half its health when I did it.
7: The Knights of Gonk mission doesn't count for this achievement since it's not an escort mission.