for me the best way to promote bitcoin is by using websites not just social media used some different websites that make your refferal,,, good looking website to attract more people to click and get on your links, and it is friendly no need to log in just click the site and then they can see your refferal asap.
But it boils down on how can you attract people in your website to click on your affiliate? Then it will go back again to social media's (FB, Twitter, IG and others). Not just good looking websites but you also need to put a lot of quality content in it. If you have this qualities plus social media promotion then you will get a high chance that you can get a potential customers or someone will click on your affiliate links.