You don’t have to stand directly in front of a door to open it — stand to the side instead. This is just good practice. There’s no reason to stand in a doorway when you can just inch over to the side. Even houses you’re confident no one occupies might have a sneaky person inside waiting for you. Bounding straight through doors the second they open is just asking for a chest full of lead.
Additionally, use windows to check the insides of buildings when you find them. Closed interior doors usually mean a place hasn’t been checked by another player (although not always). The state of doors can give you a quick bit of information and help you avoid getting blasted as you enter a structure. In the reverse, closing the doors near windows can trick cautious players into wandering into an ambush.