Be a good student
In order to have the ability to confuse others through big words, you got to have a very strong grip on vocabulary and enhance it as much as you can. Most of the people do not go through dictionaries and search for words, so if you can use uncommon words, you have a great chance to play with their minds.
You have got to work extremely hard on your studies and concentrate on having a very bright academic career, which will naturally help you increase your vocabulary and the mental sharpness, which is needed to confuse others.
Work in a call center or become a writer
People, who work in a call center, do have extremely high communication skills as this is the requirement of their job. Even if you do not wish to take this profession as your career, you should look to work in a call center for a year or two. It will immensely enhance your ability to convince others. Persuasive communication is the thing to learn as a call center representative because selling things over the phone is one of the toughest jobs of the world.
Apart from working in a call center, you can work as a freelance writer as well. Writing blogs or articles will help you improve your grammar and you will naturally have a bigger pool of words to play with.