The easiest maps to do this on are High Ground and Snowbound. They both have vehicles and are small maps. I have done this achievement twice on both and found it pretty simple.
As soon as the match begins, try to avoid other players and find a Ghost. It doesn't have to be a Ghost but they are easier to get away in if your being shot at. Also, most players will rarely try to hijack a Mongoose or Warthog so the Ghost is the best to try.
Now, the trick is to find another player and drive the Ghost right next to them. Don't splatter or shoot them just stop the Ghost as soon as you reach them. The player should hijack you. If they don't, drive away and then go back.
Once they do, drive the Ghost full speed into a nearby wall, tree or whatever before they kick you off. If done correctly, by the time they turn the Ghost around, you can successfully hijack them and unlock the achievement. Sometimes players will speed away in the Ghost once they have control so try to crash it just before you're kicked off and you should have no problem.
Some of the best places to try are small areas like inside the underground passage on Snowbound or inside the base on High Ground. The other player won't be able to escape quickly if there are too many nearby objects.
Here is a video showing how I got the achievement: