Obvious

Iaman extracts the essential points from Improve the Credibility of Your Witness: Undesirable Verbal Witness Characteristics - Litigation Insights:

• Be forthright, Evasive = Hiding Something.  Witnesses who are viewed as “evasive” lose credibility with jurors.
• Be succinct not verbose.  Jurors criticize answers that are “verbose,” “long-winded” and too technical.  Jurors like answers that are relevant to the question.
• Limit the Technical Jargon.  Know your audience, use language they can understand without being condescending
• Prepare to Answer the Tough Questions. so you don't  hesitate or “push back".
• Lack of Internal Consistency among Witnesses’ Testimony.
• Be familiar with your documents.  .  Two overarching positive factors that influence jurors’ perception of a witness’s credibility are appearing knowledgeable on the topic and speaking confidently.
• Avoid powerless speech as defined by the presence of linguistic speech markers such as hedges (e.g., “kinda,” “sort of”), vocal fillers/hesitations (e.g., “well,” “ah,” “um”), disclaimers (e.g., “this might be a bad idea…”) and tag questions (e.g., “…don’t you think?”).
• Avoid Tag Phrases.  When witnesses use phrases such as “to be honest” and “to be frank,” they beg the question of whether they were telling the truth or being frank prior to this statement being uttered.
• Avoid Social Fillers.  The use of “um” is a socialized vocal filler; that is, we have learned in conversation that when there is a silent pause when talking, it is an indication for someone to interrupt.

Isn't this obvious? Umm, maybe not. One mistake I have consistently made is that I assume that because something is obvious to me, it is obvious to everyone. Only later when I have put a plan into motion did I discover that, no, not everyone understood what was going on, witness this video:

MIT graduates cannot power a light bulb with a battery. It isn't just MIT that has this problem. Our entire educational system is built on being able to manipulate  words, not things, and we kind of assume that because people can talk about a subject they actually understand it. Obviously, that is not the case.