Try to promote your affiliate links in websites that have a lot of members and that watch ads. Traffic exchanges don't bring you many conversions but is a good free way of advertising your links. If you want better result you could try to buy a fixed ad daily with your referral link in big PTC sites. Neobux is known to have a user base that are also interested in bitcoin, however their cost is not cheap, 100 dollars for a day for your affiliate link and results are not guaranteed.