Dress as a successful business owner. Actually, once you've made the sale, the best thing is to shake hands with your new customer, thank him, and leave. A little small talk after the sale is appropriate, but becoming too friendly is not. You create an impression, and preserve it, by maintaining a business-like relation ship. When you go to make your cost estimate, take along a ruled tablet such as those used by elementary school students, carbon paper, a calculator and your appointment book.
Some people find it easier to work with a clipboard and ordinary blank paper with carbon.
Later on, you may want to have general checklists printed up for each room in the house, with blank lines or space for special instructions. Simply identify the specific room at the top of the sheet of paper, then lead your prospect through the cleaning steps of each room, covering everything in it. Finally, when you've gone through each room in the house with the prospect, come back to the kitchen and sit down at the table. Take out your calculator and add up the time you estimate each job in each room will take to complete. Total the time for each room.