What are some things that a good mentor does?
I have been lucky to have several strong mentors during my life. A mentor back in college encouraged me to run a half marathon (without my knowing I was doing it), by taking me on a well-planned jog, with water bottles placed along the way. More recently, a mentor has encouraged me to "share my work" with others, suggesting that to do otherwise is a waste of talent and resources.
A good mentor helps you to become your best self by complimenting the areas where you shine and highlighting the areas where you are holding yourself back. They don't offer unjustified praise, and they may ask some hard questions, but they are often reflective people who encourage you to be your most authentic and best self.
A good mentor shares their ideas and encourages you to do the same. They encourage you to show your work, even when you think that it's not quite good enough to share with the world. They encourage you to take risks and to step outside of your comfort zone. Recently, a mentor encouraged me to teach a workshop about copyright for other educators. I haven't done it yet, but I'm seriously considering it.
Good mentors listen well and ask open and honest questions. They tell stories about their successes and their failures. Informative tales of failure and uncomfortable struggle are not stories that just anyone will share, so having a mentor open up about the difficult times as well as the good times is incredibly valuable, humanizing, and rare. If you've found one of these people, do your best to keep them in your life.
A good mentor is real. They laugh and cry freely. They aren't trying to show off or show you up. They are happy to see you succeed, and they are not threatened by your successes. They seem to have enough time to share with a large circle of people, even though they are usually quite busy.
A good mentor has a great deal of life experience. They are not one-trick-ponies, but people who have had varied experiences to draw upon, making them experts at giving advice if you ask for it.