Achieving rapport with someone may come naturally, but it may not. There may be good chemistry, there may not. If you are having difficulty, then the way to establish rapport is to enter the world view of the other person, to accept their view of the world. Moreover there are subtle techniques you can use such as matching body posture, maintaining eye contact and matching breathing rhythm. Some of these techniques are explored in neurolinguistic programming, a branch of psychology. If rapport is established, then instead of being out of step with the other person, you are in step. You find that you have built a foundation for a more effective give-and-take relationship. Your point of view receives more generous consideration.
A classic if unusual example of rapport can be found in the book "Uncommon Therapy" by Jay Haley (ISBN 0393310310), about the psychotherapeutic intervention techniques of Milton Erickson. Erickson developed the ability to enter the world view of his patients and, from that vantage point (having established rapport), he was able to make extremely effective interventions (to help his patients overcome life problems).