I firmly believe that repeat business will happen ONLY if you do a great job, including some extras the first time. Another point: I always speak with a new customer, to find out what their intentions are. Is this just a one time thing, or are they looking to have someone regularly? I always ask questions about the house - what kind of kitchen counters, appliances, what sort of bathrooms are there? Is there a glass enclosed walk in shower? Are there pet in the house? Children? Most important is this: what is this new customer's expectations? Sometimes when you dig a bit deeper, you find out that this person EXPECTS beds to be made, trash taken out, etc. It is up to the professional to decide if they want to do these things, since they are not a part of normal, standard cleaning (in homes, anyway!) That stuff takes extra time, which you should be paid for. I always tell new customers that regular cleanings are a process - by which I get to know how the customer see their home. (Which isnt necessarily how I would see it!)
If you are careful how you word these questions, no one will be annoyed. They will get the impression you truly care about their needs. And that is a great way to start repeat customers!!