Plant - There are a couple good areas to shoot but my favorite is near the health pack (on the right, near the area that usually spawns a bazooka) so I can grab it when I'm running low. A good spot are the left & right areas near the acid with the weapons. The second level is just a bit safer, but if you like to shoot really easily, then you should go to that area below the second level.
Abandonment - Inside the house is a really good area. Nobody really comes into there. The AI stay away from it even though that's where actual players should go. There's some other good areas but I don't play Abandonment that much, so I'll update it.
Stranded - Possibly the best level to hide in, the right are could be better because there's more sniping room and better guns (more spawns) and there's health on the right spawn area. The underground area on the left side is good, too.
VR - Well... there's not really many good things to do on this one.
The Last Stand 2 Stay in the middle of any shooting area.
