Sadly, the public speaking circle has its fair share of individuals who think they have a right to be treated better than anyone else. Conventions of public speakers are quite a sight. It's like battle of the egos, and to be perfectly honest the really big names tend to stay away from such gatherings. I know of a number of speakers who at one time threw a tantrum or acted in a very demanding way while being paid to speak, word subsequently spread like wildfire, and they found themselves waiting a very long time before receiving any more bookings.
So now that you've seen a clear picture of the negative side of things, let's talk about general etiquette and manners. If you are invited as a guest speaker, make an effort not to be demanding. Treat everyone courteously and with respect. Be aware that hotel staff are often overworked and they simply may not be able to react to your request for a jug of water as quickly as you would like. Build a reputation as being easy to work with and you will benefit greatly in the long run.
Etiquette while on stage also deserves your consideration. Speak in a way that suits the circumstance and audience. Sometimes this may mean being very formal, addressing individuals as Sir, whereas other times it's preferable to be down to earth and colloquial in your speech and etiquette.
It is the opinion of the author, and many other experienced speakers that bad language (swearing) is never acceptable. Even if you think the audience will be fine with it, you can be sure that you will offend someone, so it's just not worth it. Besides, swearing is usually used as a substitute for someone who has poor grammar. A person who avoids swearing will always be treated with more respect than someone who litters their presentation with expletives (even if it is done as part of a joke).
If your presentation is a formal affair or you are being paid, it's a kindness to express thanks to everyone who has helped you. Commonly this includes the company that hired you to speak, the organisers, the technicians, and of course the audience for their attention. Don't draw this out into a long speech, a brief mention is all that is needed, and you can be sure that it goes a long way to all those concerned. Apart from being a common courtesy, it will cast you in a positive light and you'll be remembered for it.