It took at least 2 years for us to get listed in DMOZ. Only submitted one time and followed their instructions to a tee. Think the main thing is to be able to write an objective non-salesy description for you website, then it’s just a waiting game until someone finally gets around to looking at it. And, yes, your site probably needs to stand out a bit from the other 100,000 that are also trying to get listed in the Online Gambling categories. Finding a niche category is helpful.