In PUBG, one of the hardest things to do is to push players inside a building. There are a lot of building in PUBG with different kind s of structure. However, most of them have only a few entrances, making it very easy for people inside to tell where you will be. Furthermore, buildings are good covers to defend people from outside, especially in places with few obstacles around. You enemies will have more information than you can plan out ahead to prepare for your push. Here is what you can do to create your own advantage and send those camper in buildings back to the lobby.
Approaching the building
Here, you have two option to get close to the building without getting killed.
If you don't have a vehicle, getting close to a building with people inside through open space is a very bad idea. People scouting around their building through windows very often. You will have little chance to survive if you get caught. Instead, be sneaky and move from covers to covers to expose yourself as little as possible. If there aren't any or few covers around the house, try to approach the building from the side that doesn't have a window.
If you have a vehicle and decide to rush to them, there are a few things you might want to keep in mind. It is very important for you to learn to drift your car and slam it against the wall because it is the most effective and the fastest way to stop your car and quickly get out. It will also stop the enemy from having a shooting angle at you. However, you can't just slam your vehicle into a random side of the building. Choose a side which the enemy can't see you through the window. Here are some of the examples.
One last tip, with the latest update, you can now turn off the engine of your vehicle. Now, this is actually a very huge change as you can turn off your engine while you are driving. And what does this do? Your vehicle will still be moving for a considerable amount of distance while making no sound at all. This way you can easily get close to them without even being noticed.
How to fight
In the early game, if there is an enemy drop at the house right next to you, it's best to grab a gun quickly and rush them before they do the same to you.
However, in the later phases, that is no longer a smart option anymore. It's best to rotate around the building and find small openings to kill them. Sometimes, if your opponent is smart and knows that you are out there, they will be more cautious. In situations like these, what you should do is keep rotating around the building to confuse them. Use frag grenades to force them to make a move or die, both will benefit you. Stun grenades and Molotovs also work very well here. Use multiple Stun Grenades at a time to make sure your opponent is blinded.
Lastly, use crouch walking to sneak into the house without making any noise or footstep sound. They will never know that you are coming.