To be able to get to high ground and get to good places to Air Stomp I'd recommend the following kit.
-Feline/No Attachments (I know its OP but it has the fastest move speed)
-M12/No Attachments (fastest)
-M34 (to stop them leaving if you need to)
-Air Stomp
-Covert Ops (so they don't hear you, so you don't get taken out by the Ceph on your high ground, and so you hear them better)
-Mobility Enhance (to get to, and back to your high ground)
Try it on Skyline, on the highest point, stay there until someone comes to the main roof by the broken water tower and elevator shaft building. You can obviously do it other places, but mostly stick to there until you get better at it. If you see people farther away, tag them. If they're out of your range your teammates will get them, and if they come to the roof you've got a nice red arrow to Air Stomp at