The key to success as a presenter or public speaker is the pursuit Peter Bender mentions ins his Secrets of Power Presentations where he says:
" Pursue the goal of excellence in both knowledge of your topic and your ability to present it. Halfhearted wishing will only bring disappointing results."
Good advice and that pursuit should include words as effectively as the tennis player uses his or her raquet to to put the ball exactly where she wants it.
Become an avid reader in not only your own subject area but many others and then practice, practice, practice, using new words, ideas, and illustrations you learn in your own written and oral presentations.