The amount you are going to charge will depend on many things and that advice is not really meaningful on a forum.
Have a charge level in your mind, per sq foot, metre or per room but be flexible. You could, as I do discount for quantity. There's no need to explain all this to your prospective customer. Do your survey, after a while you will be able to go through the job and do the simple calculations in your head. Some will habitually use a survey form and scribble down as they go along in order to look more professional, but I've never found the need. It's about how you approach and appear to the customer just as much about pricing.
The customer will have an idea of how much they are expecting to pay, for some what you quote will be more than that, and for others it will be less. If you are confident and appear to be knowledgable they will pay the extra. They also have to like you straight away, within the first few seconds of meeting you, or you have little chance of getting the job. Don't think you can get away with bullpoop, bluffing your way along, they will pick up on it, make sure you know what you are talking about. Above all be honest, tell them the truth don't promise something that you cannot or are not sure you can provide.
Note. Bullpoop is the admins censored word for, you know what.
