Many people tend to think that a defense attorney automatically knows how to impeach or "chop up" a witness who is testifying on the stand. Unfortunately, that's not always true. Some attorneys are natural cross-examiners, while others have to work very hard to figure out what to do. Here's a short guide on how to impeach a witness on the stand. First, take copious notes when a witness is testifying. Make sure to listen carefully for those bits of testimony when the witness takes a specific position on one thing or another and note their words accuratey. This is especially important when the testimony is about something that is critical to the District Attorney's case. I'll explain the rest fo the process in the next section Once you have that piece of testimony noted, look for the next and the next until you've amassed a substantial enough group of items which you know you can impeach them with during cross-examination. Then, before standing up to cross-examine, compose yourself and find the impeaching evidence and make sure to mark it so that once you've started your cross-examination, you'll be able to use the information to show the inconsistency between what they've said before and what they're now saying at trial.