"When one teaches, two learn."
We all have heard of this principle but do we apply it? I like to tell the people I mentor that they are vessels full of information, and do not worry about being judged; it is the information that is important.
You can relax and provide information in a supportive manner. You never want to come as you are trying to have the person feel you are talking down to them.
The best people I work with are good listeners, and pace their presentations at a speed the listener is comfortable with mastering. The eyes of the learner are a great way to see if the listener heard you.
You should also ask qualifying questions like:
"I went over that fast, what points did you pick up?"
"Based on what I said can you give me an example of how you might apply it?"
"From your past experience, do you see any flaws in what I said?"
Try it and see if it works for you.