Hi Douglas,
I know I'm coming into this conversation a bit late, but I have a lot of experience working with escort sites that I'd like to share, just for anyone else who may be facing similar challenges.
As others have pointed out, there's a serious lack of resources for marketing and building links to escort sites. And at the same time there is a lot of competition for top rankings, especially in the UK market. Because of this, many SEOs rely on link trading with escort directories and even resort to link spam. In fact, many of the top ranking sites for escort terms sit on mountains of spammy links. Some get penalized quickly for these methods while others don't. Such is the nature of any industry lacking relevant link building resources.
The best way for both escort directories and agencies to rank well is to negotiate non-reciprocated link deals with the websites of independent escorts. Many escort sites ask for links in exchange for listings and exposure. Some sites may require reciprocal links, which is fine as long as you keep them to a minimum. Acquiring too many of these links, which are viewed as link trades and go against webmaster guidelines, can be risky.
Another way to get quality links is to reach out to the many escort blogs floating around the industry. A lot of times these blogs are happy to work with agencies and independent sites if value can be provided in return.
Escort directories are another option, but as with link trading it's important to keep these links to a minimum. Even if you see lots of directory links in the link profiles of other top ranking sites you can't be sure over what period of time these links were acquired.
You can also tap into the adult industry for links. Many adult webmasters operate escort sites and blogs which they use to funnel traffic through paysite affiliate links. Even if the content on these sites lean more toward adult models than escorts, the relevancy signals of the sites will still work in your favor.
Also, as with all campaigns, you'll want to perform a full backlink profile audit to make sure you're working to remove bad links from the past as you're building new. There's some details on how we do this here http://www.adultseopartners.com/escort-seo-strategy.html. It's possible that some of your struggles may be due to the negative effects of old links that were built before you were brought in.
There's more ways to get links to escort site than these, but in my exprience these pack the most punch. And keep in mind, the more relevant and quality links like these you have, the more you can get away with lesser quality links.
