Most professional roles require you to give advice to others, often to people more senior to you. In the strategy document you write for your manager, the presentation you give to the Board, even in your verbal briefing to the CEO, at each point you are using your abilities to influence and persuade. Indeed many of us spend most of our professional lives trying to become effective and trusted advisers to our bosses or clients. For the consultant, particularly, there is probably no higher mark of success.