Personally, I find all my drawings look like a Chimpanzees tea party, whether on a whiteboard, piece of paper or anything else. And practice doesn't work - I've been practicing for over 30 years, since I was old enough to hold a crayon, and my drawing skills haven't got any better!
I agree with previous advice - make it a line drawing, keep it as simple as possible, and don't talk any more than you have to whilst actually drawing. Then, explain what you've drawn. And if it really doesn't look anything like the real thing, I find it helps to make a joke about my lack of drawing skills.
(As a matter of interest, I've been practicing my singing for about as long as I've been practicing my drawing, and that hasn't got any better either!)
FFF
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