i can tell you that you can never "increase" your energy.
but you can be able to control more of your own energy.
you can easily do this by concentrating on what you are doing.
as an example.
if you do or thing of several things at once your thoughts and energy will be spread. but if you learn to concentrate only on what you are doing then your energy would be much stronger and whatever you are doing with it will come out much better, with magic and everything else you are doing in life.
the best way to learn how to concentrate better would be by meditation, but not in a quite place. try rather to meditate at a noisy place end learn how to close yourself of from what is around you.
if you can do this then you may feel it as if you grow stronger, this is because your mind would have evolved a little bit and everything will be much easier.