For hookers you can visit the Pub and spak to either of the two female customers. You get contacts (entries in youir iSnatch.sex list) from crusing in your vehicle and throwinf parties; these you'll need to convert into a Fuck Buddy before making a hooker (or actress). You can also steal grisl from the Street if they are unprotected, eithr from other players or from the Unknown Pimp. There is the flyer 'event', which now looks to be a permanent addition. And, of course, buyng packs and bundles.
There's probaly other ways and I am sure Jack will correct me on the ones I have missed! :)