If you see a lady that fits your taste smile at her. If she smiles back approch her and say 'hello'. In most cases she will ask you 'where you come from', then she will ask your name and likes to know where you stay. After that Pattaya and nature take their course easily and hassle free. Please be polite: Don't touch her until she takes your hand or your arm. Do not touch her hair or her head.
In Thailand the head is the most important part of the body.
It's 'the home' of the soul and the spirit. Do not kiss her in public.
Even if your lady is a prostitute (in your understanding), she is a human and a Thai - and Thailand has its very own rules. Wear good and clean clothes.
Look around, in most cases Thai women wear nicer clothes than their counterparts in Western countries. Take a shower (and use a deodorant) before you go to a bar.
Remember: A man's freshly showered body is the greatest turn-on for women. Try it - at Pattaya Beer Garden! It works.