I've been pretty lucky to have great mentors on my start up journey.

The best way to find great mentors is to make a short list of your ideal mentors and contact them. Let them know you are looking for a mentor and want to build a long term relationship. If they agree to meet you and there is chemistry, you should be well on your way to a long and sustainable relationship.

The most important thing to keep in mind is that your mentors are giving up valuable time. If you go in to your mentor sessions with a know it all attitude and don't listen to their coaching, i'm afraid you won't have a sustainable relationship. Don't forget you are there to learn from them, and in the ideal situation, they will learn from you.