Gather as much evidence as you can about your rendezvous. Do you have any photos from the night in question, or text messages from the person you have slept with? Will any of your friends vouch for you? Decide how you'd like to be photographed. Would you consider pictures in lingerie, or would you prefer to be dressed in evening wear? Make this clear from the outset Decide how much you'd like to earn, but be realistic. Most kiss and tells earn between quite a bit of money,per story, and higher figures only come if you have slept with someone really famous, who is married, and you have considerable proof about the interlude. Contact an expert who can guide you through the process. They will negotiate with a range of newspapers on your behalf and manage your contracts for you. Sit back and wait for the offers to come in.
Don't bother kissing and telling if you are prudish, or don't want your parents to know what has happened. If you are in a national newspaper, your parents are likely to hear about it. The publication who runs your story might consider allowing you to change your name, but you will need to be photographed. The more proof you have, the higher your fee.
Do bear in mind if you have a job, your employer might not approve of the article. Your parents may take the same view.