The man who has to speak in public, must be fought with all sorts of speech disabilities. If available, do not hesitate to contact a speech therapist, despite the adult age. The view that these specialists only work with children, is fundamentally wrong.
Do not paint the speaker and voice on a single note. Often the speaker does not notice the monotony of the speech. Record it using a recorder or computer and then play. If you speak monotonously, you will notice it. You will learn how to change the tone of voice from the beginning to the end of the sentence depending on whether it is affirmative or interrogative.
Pay attention to the content of the spoken phrases. If there are no multiple repetition of the same words? Can't some of them be replaced by pronouns and synonyms?
Fight the tautology. A few consecutive words that have the same value, without loss of meaning be replaced by one word.
Correctly aligned words within a sentence, even if it is difficult.
If you do not know the meaning of a word, either learn it or refrain from using the word. Never allow liberties in the use of phraseology. Before you use any of them to find out how it sounds exactly. Also, don't use in relation to nouns adjectives, they do not fit.
Get rid of the habit to dilute it words-parasites. Without the words "here", "well", "means" and similar is possible to do. Also clean it from jargon. Replace them professional terms.
Improving communication skills is impossible without taking into account the experience of others. Read and listen to well-written texts, and will not notice as you start to speak better.
Finally, never read the text with a sheet of paper, a laptop screen, phone. Make a short plan of speech to occasionally look at him, and the rest remember. Before class, be sure to rehearse, to be sure, I remember that all is well.