There are many ways to define personal power. Here are some to consider.
Now, of course, power can be used positively or negatively. It has been said that being forceful is the weakest power of all. Brute strength often only yields negativity and resentment; and only short term gain. A much stronger use of power is to use charm and positive influence to help others build their power. This is a much longer-lasting strategy with easily seen benefits including increasing the power of the initial charmer.
Be an observer of yourself throughout your days. Take periodic attitude checks. Begin to recognize when you feel apathy, negativity, or just generally stuck. Use those feelings as a signal to alert you that you have lost touch with your personal power. Once you are able to recognize what it feels like when your power is depleted, then you can start to experiment and find what works to make you feel powerful again. At that point, you will be cued into a key cycle that you can use to manage yourself to success.