Showing that someone is special

How do you show someone that he is special to you? The question came back to me during my recent trip.
Should it be done in words (saying "I love you" regularly) or do actions (visiting as often as you can) speak louder than words? What if someone refuses to see the positive signs of admiration, and focuses on what he thinks are other loved ones in your life? How can I prove that someone is special to me - much more special than other friends that I have.

Likewise, how do you know what someone feels for you? Should I take his words literally - even if the words would hurt me, or should I read between the lines and put the words in the context of his personality? But then I am playing amateur-psychologist and I may be totally wrong in my conclusions. Or should I base my interpretation of his feelings on his actions which are so much more positive than his words?

And how to reconcile my doubts about his feelings with my attraction to his personality: the fact that he is not an easy book to read adds to his attractiveness. Would he be like me, I might have been bored with him - the fact that I need to keep working hard for his attention keeps it interesting.

And finally: if there are other friends or fucks how can we prove that they are just that: friends or fucks. Infinitely less important than someone who is a friend AND a fuck AND a soulmate.