Few people need more help building charisma than I; fortunately author Cabane provides it in 'The Charisma Myth.' The bad news is that the material should have been condensed and better structured to make it easier to follow.
Cabane contends that becoming more charismatic doesn't require transforming one's basic personality - rather its about adopting a series of specific practices that fit into one's existing personality. He introductory tips, however, are rather mysterious and probably ineffectual by themselves - lower your voice at the end of sentences, reduce how quickly and how often you nod, and pause for two seconds before speaking.
Continuing, she declares that presence, power, and warmth comprise the three core elements of charisma. 'Presence' involves having one's total mind involved in a conversation. In short - make the other person feel like they have your 100% attention. Clues of power come from one's appearance, others' reaction to this person, and his/her body language. Warmth tells whether or not people will want to use their power in our favor. Selling a vision, expressing gratitude, compassion, and interest in people are essential.
Evidencing physical discomfort (eg. reacting to a hot suit, glare of the sun) can undo charisma by impairing one's attention. Ideally one would prevent the discomfort. Explaining the problem and taking action are important second lines of defense, if needed.
Self-doubt undermines charisma. Cabane tells readers this is normal. Practice, practice, practice on presentations helps replace self-doubt with confidence. A good appearance (clothes) and positive handshake also help.
The 'Ben Franklin Effect' - ask an opponent for help, borrow something from them. Criticize behaviors, not the person. Simplify presentations, use analogies, make statistics personal, keep presentations short, remain calm, articulate a vision.