It depends on the subject matter. For personal finance, it's pretty easy to digest and learn yourself through reading. It's black and white stuff. You see it, you process it, then it's up to you where you go with it.
For "arts" like woodworking, painting, negotiating, general life advice, running a business, etc, I think 1 on 1 interaction is much preferable. You can certainly learn a lot by reading and your own practice in these subjects, but the time given to you by another individual who is already highly skilled in these areas is invaluable, if not for solely their unique perspective.
So, finding a mentor I think is the easy part. Knowing exactly what you want to learn and being motivated to learn it is the hard part. There are plenty of people out there willing to talk and share what they know.