When you have secured an area, don't forget to tell the enemy. If you are short of everything, except the enemy, then you are in the combat zone. Try to look unimportant. They may be low on ammo. The easy way is always mined.
Tracers work both ways.
Incoming fire has the right of way. Teamwork is essential. It gives them other people to shoot at. Never draw fire - it irritates everyone around you. No combat ready unit ever passed inspection.