To me, a mentor is someone that is living the life that that you want to live and is quite a bit older. They've already accomplished the goal you set out to reach. It could be that they've created a lifestyle that you want. They are the people you ask advice on for the large life decision moments.
For example, do you like the relationship they have with their spouse and kids? Have they created a business that allows them to spend time with their family? Think about exactly what you want to accomplish in your life before seeking out mentors.
If you're looking for someone to give you marketing or sales or HR advice, you're more seeking an advisor that knows a particular field.
Let me know if you'd like to talk about how to find top notch mentors.