I have two options,
and I chose depending on the gameplay.
Option one:
If everyone is rushing, of course, I'll sit and camp.
No, it is not "noobish" it's tactical.
I'll pick a spot where I'm not seen, and people constantly flow throughout that area.
Also, for camping.
Stay in the same area, though DO NOT stay in the same position.
Pick a area, and learn to work with your surroundings, use what's around you to YOUR advantage.
Option two:
I rush the base.
Obviously, the main objective is to kill everyone who crosses your path,
though what everyone gets mistaken for is chasing after one person.
If a person runs another way, and you're being fired at.
DO NOT, I repeat. DO NOT fire at the person running away.
Ensure your safety, then you may or may not chase after the person who got away.
You want to remain unnoticed, why would you want your position known by your opponent?
Hope I helped.