When you present eyewitnesses, you do so by asking a series of questions. First you need to establish that your witness has personal knowledge of the event in question. This normally means you must show that your witness personally observed, heard, smelled, touched, or tasted whatever he is testifying to. For example, ask questions to establish that your witness was on the spot and overheard the contractor you are suing talking to someone about the details of your garage job. Second, you must learn to ask questions that allow that person to explain whatever he knows that supports your case without putting words into his mouth (called leading the witness). You can learn the basic techniques of how to question a witness and how to object to any improper questions asked by reading Represent Yourself in Court: How to Prepare & Try a Winning Case, by Paul Bergman and Sara J. Berman (Nolo).