a normal service 'creaton' that most ladies all provide is the base service of french (oral) on you, body slide, massage and sex. Then there are the extra's available. some ladies may include this in their price but as some laides only provide certain extra's and not all of them you need to know in advance what to expect. If your looking for a particular service make sure you ask if its included.
you can also tell the receptionist what type of service you want and which ladies would they recommend.
Intro's are great if your experienced but the ladies have to learn quick how to sell themselves in a short time and for the inexperienced punter may not give you enough time to determine who would suit you and someone looking great, may not turn out to be so great in the room.
Lounge scenarios where you get to sit and meet all the ladies and chat to them till you find who your comfortable with may also be ideal for a newbie, but once again tell the receptionist you are new and a little nervous so she can help you out. If she doesn't, then she shouldn't be a receptionist.
Other ways are emailing porivate ladies if you can and set something up in advance, chatting a little about yourself and it being your first time and see how she responds by email.
Extra's can include in services: mutual french (oral) on the lady, toys of vibrators to use on yourself or her if she allows. affection and affectionate kissing (doesn't have to be tongue as that is quite personal) those ar the main extra's but you can also advance from there and get anal sex, golden showers (which is urinating on you) light b&d which may not be your cup of tea, domination, submissiveness etc.
Use the internet to find out what sexual services there are.
Don't go in worrying about your weight, you pay them to have sex, find someone who approaches you with a genuine smile, tell them your a little nervous and see their response to you.
They see all sorts of shapes and sizes and it doesn't really matter that much to them. Bit of womanly advice, try and go for a sexy maturer lady, who may not look as fantastic as an 18 year old, but she'll make sure you have the best damn sexy time ever as they are from the old school and the service is very important to them, where sometimes the younger one's are more in to just the money. (Not all of them either) Price can determin service also.
You will have to use your own wits to determine who fits what description, and if you luck out in the first go, then go back for seconds instead of giving it up, as you can go to a restaurant and have a crappy meanl, but its not liek that each time.
Good luck mate and let us know how you go.