The Tarot spread is an important part of any reading. The spread is how you lay the cards out when you are answering your question, and it allows you to correlate a specific card with a specific aspect of the answer. For instance a particular position may indicate what the hopes or fears of the querent (the person asking the question) are.
The most well known spread is called the Celtic Cross (pronounced Keltic). This ten card spread is a good spread for giving a general answer which includes the past, present and future as well as mental, emotional, and physical planes covered in layers and other things that can be interpreted usefully. Unfortunately it is so well known that many people use it exclusively. This becomes a problem because not all spreads work for all questions.