To recover energy, you need to increase altitude and increase or maintain speed. This means putting it into a steady climb. There is no way to do it in a pressure situation. The trick is to maintain more energy then your opponent(s) until you shoot them down.
You can trade altitude for speed, and speed for altitude and maintain the same energy level. You loose energy when you have more drag then thrust. You increase drag when you turn. The higher G turn, the more drag you make.
Many people associate just Boom and Zoom (B&Z) tactics for energy fighting. I am not talking about B&Z. In an energy fight you will loose energy because you need to turn to keep your enemy burning energy. The art is to use less energy. When you gain the advantage, you can then set up and kill him.
You need to learn how to make a fast low energy turns. They are like a high yoyo. Try to limit your turns to 5G. It take lots of practice and much patients, but it is quite fun
Best to find a trainer, I am sure they can help. I have an old film here:
Energy Film Note the speed and altitues of both aircraft at the beginning of the film, and at the end of the film. The FW starts with quite a large energy advantage.
My first few turns were 5G, but I had to pull more as the fight went on to avoid getting shot. But the FW was pulling hard to try to make the shot, bleeding more energy then I was. At the end, he lost the energy advantage and ended up slow and in my sights.
Gunner