Sensing energy is pretty simple. It is more about changing your mindset than anything. Although a lot of us do come with natural sensors we tend to ignore them or only feel them at certain times.
To begin with simply close your eyes and start to focus your mind, let it clear like if you were doing meditation and focusing on yourself. Once you get to that point you will need to shift your focus from yourself to the place/room around you, feeling and listening to it and the energy it contains. To note it will or can take sometime to get used to this as it can shock the system slightly much like your first OBE experiences.
You continue doing this until you can hold it, once that happens you can work on doing it so its just something you do naturally by practicing it.