The first red flags for me are a website that doesn't show photos of a proper, well equipped studio and of the Domme in a variety of fetish wear. The latter perhaps less so as some Dommes ( NYC's Troy Orleans for example) don't session in "costume". Lack of a list giving major pieces of equipment and gear owned is also a giveaway.

There are enough quality, well equipped Dommes around that I can't understand why anyone would session with someone working out of her apartment with little more than cuffs and a crop but still charging top dollar.