[Moody_10001]

I would suggest that social media would be great especially through publicly available platforms like Twitter, or professional centric platforms like LinkedIn. With keyword searches, you'll be able to find professionals that match your criteria, and by monitoring followers and engagement level, you can determine a person's reputation and willingness to talk with others. Never lead with an outright request, however get to know your hoped-for mentor first; and, if you can, offer something of value to begin the relationship.

[Moody_10001]

I second this. Look for facebook groups, online forums, or subreddits where you can interact with experienced programmers. There are many articles written about all these different places.