On the previous day only we had booked our tickets for the Show. However you can do it in person as well and in case you plan to do so, do reach the theatre well in advance. If you want to book online, better to do a day before as there are chances that the Show might be sold out.
Alcazar Show is basically a dance show where mostly transgenders will present to you some of the beautiful cabaret dance forms of Thailand. It is totally family friendly and you can enjoy with your family and friends alike. You can also click pictures with the performers after the show at a charge of 400 Thai Baht.
So this is my suggestion for a typical 2 day Pattaya Trip. I personally feel 2 days is the right amount of time to explore this city. 1 night will also be fine if you are ready to sacrifice either Alcazar Show or Pattaya Nightlife. If you plan to stay on for a 3rd day you can take the day tour to Coral Island near Pattaya.