The most basic way to promote bitcoin is to advertise it on social Medias. We all know that this is the most trend site in selling, advertising and even in making political issues. So if you want to promote something just post all the details their and surely many people will see your posting. If you want many people to see and share your post you must post the good benefits of the thing you are promoting. In the case of bitcoin I strongly suggest that you must post the good benefits of it like on who much you can have money with the use of bitcoin.