I only work on tour and only do incalls so my screening may be a little different to other workers - you should find what works best for you rather than follow someone else's rules.
A lot of mine is about my gut instinct.
1. I won't arrange bookings via text or email without speaking on the phone, even if it's just a brief conversation. That phone call is my chance to listen to my intuition and turn the booking down if I get any bad vibes. (If it's someone I've seen before and have marked as OK then I'll take bookings by text.)
2. If anyone sounds like a wannabe gangsta, e.g. "Yeah babes you available now innit?" then I miraculously become fully booked.
3. Anyone slurring their words or otherwise sounding intoxicated will not get a booking.
4. I offer two levels of service - when they call I ask "Was that for GFE or VIP?" If they ask me what the difference is, I text them a link to my profile and to give me a call back when they know what they want. (They won't.)
5. My profile always states that I'm in a hotel and an approximate location. If they start trying to get the location out of me without mentioning an actual booking, I'll bin them.
6. If they want a short notice booking (i.e. within the hour) then I'll tell them to text me when they're setting off, and ask them what time that will be. If there's a huge hesitation then they're probably not going to show up.
7. If they want a booking for later in the day then I tell them to call or text 1hr before the booking to get hotel details, and if they don't confirm at that time then the appointment will be given to someone else. Genuine clients will understand this. If they start whining about "But why can't you give me the postcode now, I need to know how long it will take" then bin them off.
8. Biggest issue for me... If they ask for services you don't offer on your profile. "So do you do anal?" "No I don't." "Oh okay, can I book anyway?" No - because you're likely to be a boundary pusher, you haven't read my profile properly, and if anal (or whatever) is important to you - and it must be because it's the first question you asked - then a booking without it isn't going to be fully satisfactory for either of us, so it's best you find another provider who offers what you're looking for.