If you're a newbie, I would strongly recommend NOT to use LeoList (to find new providers.) You are right: 90% (or more) of the ads are fake. There are plenty of really good providers at the agencies (Island's Finest, Vogue Collective, The Playhouse, Essence of Asia). Then there's Tryst, a more reliable website for indie providers (although not bulletproof.)
There are tips all over this site regarding how to spot fake ads on LL (check Google images, phone numbers, etc), but I find it a HUGE waste of time (and even if you do find someone new, it's really a hit and miss.) In general, if the provider is legit (we're talking about LL), she will have at least a mention somewhere here, hopefully a review.
Good luck.