To get maximum coverage, you should install your AP in a strategic location in the building you want to use it. Also, the size and the needs of your business will determine where and how many access points you install in a building. This is true for both small, medium, and large-size business organizations.
There are some other things to keep in mind when choosing a location for your access point. And that is dependent on the model of the access point and the radio waves. Although radio waves can travel through walls, they can become weak or not strong enough (especially if the wall is thick) as one that's installed in a free location. So, if you can, install in a location where it's not blocked by a wall or behind a wall.
You have to also determine where the Wi-Fi will be needed the most. While this is obvious, it can easily be overlooked. Once you determine this location, install your access in that area or as close as possible.
Another important thing to take care of is the manufacturer's instructions. It's best to mount your AP according to the user manual since this might affect not just the performance but also the operational life of the device.