You ranking in relation to your directory links is a direct result of the ranking of the links themselves. DMOZ has some outlandish SEO rankings, simply because they don't take just anyone into their directory fold. Do not take every Tom Dick, and Harry, adding him to your directory. Look for sites that include keyword triggers that you are looking for, and with a little page rank of their own. Don't become another directory for the newbie site to spam through an autosubmitter.