I currently offer a three card spread. I use these as a past/present/future spread, to find insight on current problems, or to uncover what may lie ahead. Should you need some advice on how to handle an issue in your life, or if you are just curious about what the cards have to say, you have only to ask!
Ask a question, and the cards shall answer. This is a simple, three-card spread.
They tell what there is to know. With that said, they respond best to direct and intentional questions. If your reading seems like it is "off" it could well be that they have found and responded to a deeper question, or an unasked one. If you are ever unclear or what they have told, just ask!
I personally use the Universal Waite Tarot Deck, for the clarity of its images, both for myself, and for the customer. Though there are many decks out there, I prefer to use one that I have experience and connection with, to enhance my readings and their quality.