How to use psychic powers? The answer is "responsibly".
After learning about and developing psychic powers at least a little bit, if you have chosen well you will find good use for your newfound insights and abilities. These uses don't have to be grand accomplishments - even if they only improve your balance or psychic perception a little bit, they are good uses.
Using psychic powers responsibly means that you should generally think before you act and not bite off more than you can chew. Inflating your ego to super-size and looking down on others who haven't realized the same insights as you have is not responsible behavior either.
As you develop yourself as a psychic, your vision of yourself and of the world changes - you aim for more and set higher standards for yourself. You influence the people around you and they influence you. Acting with responsibility towards yourself and them means that the whole community you belong to will be operating at a higher frequency of psychic energy.
There are times when acting humbly is useful, and there are times when acting like a show-off gets the point across. With responsibility you more easily find the balance on how to use psychic powers.