You Can Destroy Stationary MG 42s at Pillboxes
If you run by a pillbox with an MG 42 and you are worried someone may shoot you in the back with it, hit it with a melee weapon and its toast. You can also shoot them from a distance. Its a funny way to deal with someone laying fire down from a pillbox.
Look for the Butterfly
In case you haven't realized it, the butterfly (or hummingbird or mosquito or bat) is your camera man in third person. Its a very clever idea and makes the game more fair for those that want to play first person.
You can spot them at a distance with a good scope, so look for them to figure out where opponents are hiding behind walls or in bushes or in grass. Just keep in mind if you can see an opponent's camera man.. they can see yours.