Salvage is small and fast. Use a submachine gun, shotgun, or an unscoped assault rifle. Keep your gun raised as often as possible, and avoid running through tight passage ways. There's nothing wrong with walking - slow and steady, slow and steady!
Part of the map is seen below. The "skate park" on the left consists of a bunch of concrete tubes.
The dangerous passageway we've marked out is a narrow gap between piles of junk, and anyone in the building south west of it can pick you off while you run through, so keep your eye on the window.
Running through the tubes in the "skate park" is also dangerous. Keep your weapon up, because someone is probably either directly behind you, or directly in front of you, you just haven't seen them yet...
The tubes are divided from the area north east of them by a highly defensible wall. People run through the little door all the time, but it's a terrible idea. You can see the door in the screen above. From the other side, there's a great camping spot, if you're a bastard.
It's easy to get up there, just jump.
Salvage is not a very complex map, you just need to stay on your toes, and know where to look for campers. Watch out for idiots hiding in the dog house.
Have any tips of your own? Drop some knowledge bombs in the comments!
Apr 2, 2010