What Moo Yung said. Try as many bars as possible. If you can't stand the place drink your drink (or not) and get the hell out. But try and relax and take in the experience of the place if possible. If you have experience in GG P4P bars you will be better equipped for LB P4P bars.
At Sensations beer bar (not to be confused with Sensations A GoGo on Walking Street) I'm under the impression the LBs have been told not to make the first move. Basically if you don't give them some kind of sign you want them to join you it won't happen. So a good place to observe the LBs or a bad place to be shy depending on your point of view. In Stringfellows the girls are literally almost dancing in your face as the bar is very narrow. It is much more likely for a LB to point she wants to sit with you, etc. Other bars are generally in between these two pressure levels. Not counting Fantasy Bar where they will grab you and try and pull you in off the street. 
The first couple of times I went in Cascade Bar in Nana Plaza in BKK I was very uncomfortable. Many of the huge number of LBs there were pointing at me, asking to join me, asking for a drink, etc. But I eventually realized I am the customer and I am in control. So now they can point or whatever as much as they want and I sip my beer and take it all in. If I want to talk to a girl I call her over, if not I don't. The only bar in Pattaya with that much full on pressure is Pattaya Obsessions which IMO I hate for a number of reasons.
You are in control. Although it may take a while for you to learn to really be in control. If you accidently piss a LB off just move on. More likely they will love you up if they smell newbie fresh meat. We all make stupid mistakes in the beginning. And occasionally I still make a stupid mistake.
