Usually make contact via email or Linkedin. Show your cards up front and make it clear that you're not selling anything, just looking to learn more about a specific problem you think they have. Set expectations that convo will be brief (<20 minutes).
If someone has a real problem, they will be actively looking for solutions and would be happy to chat with you.
If someone has a real problem, they will be actively looking for solutions and would be happy to chat with you.