Since negative energy is really just less positive energy, you can easily convert negative energy into positive energy. Negative energy makes you feel bad, because it is of less energy than the amount of energy you were allowing to flow through you prior to the moment in which you experience it and it thus reduces the amount of energy that is flowing through you as a result.
In order to convert negative energy into positive energy, you simply need to change the way in which you focus. By switching your focus away from a point of focus that does not allow the energy to flow through you, and by redirecting your attention towards a point of focus that does allow the energy to flow through you, more energy will thereby flow through you and you will thus feel better as a result.
For instance, if you are experiencing negative emotion, a low energy state, as you give your attention to a specific subject, you can simply improve the way in which you think about that subject by changing your thoughts to better match your desires and you will thus allow more energy to flow through you by giving your attention to an improved point of focus. The more energy you allow to flow through you, the better you feel too. Since the way you feel is your point of attraction, the more energy you allow to flow through you, and the better you feel, the better your life experience will become as a result of this decision to improve the thoughts you think.