You might already have a mentor and not realize it.

Depending on where you are in your career and who has given you advice in the past or been a sounding board...that could be a mentor.

In my career I have had mentors that were bosses and not until after I left those organizations and maintained those relationships did I ever really call them or see them as a mentor.

Look back in your career and see who did that for you and that might be the best place to start.