During my one-on-one meetings with students from time to time, I found that quite some students don't have good skills in describing things clearly (either in spoken or written English). Here I would like to ask students to do a self-check: when you find out that your listener didn't understand what you said, you may tend to say "Let me use an example (to be drawn on the white board) to explain to you."
My advice to students is that don't immediately fall back to use an example to explain what you have in mind (especially during your meetings with your advisor during which you have golden opportunities to improve your skills). If you keep immediately falling back to use an example, you will never be able to explain yourself clearly with your direct description of things. What you need to do is to revisit what you just said and ask your listener on what he or she doesn't understand, and then you will be able to diagnose "bugs" in your initial descriptions, and try to avoid these "bugs" in your future descriptions.
For my weekly one-on-one meetings with students, I demand students to propose new ideas to me and recommend/describe other researchers' papers to me. In this process, students get opportunities to exercise their skills in verbally explaining clearly new things to the listener (i.e., me).
At the same time, students get more opportunities to exercise writing things more clearly by iterating their writing with me over their research development process. See my earlier post on technical writing. In technical writing, one similar pitfall to watch out and avoid is to explain your proposed approach via only examples without direct and clear description of what the approach is. Keep in mind that examples are just sample points in what your approach covers, and often the time readers don't get to know precisely what your approach is by reading only limited sample points covered by your approach.
Don't get me wrong. I in fact encourage students to use examples to help illustrate what they have in mind in their spoken or written English. But students shouldn't rely on ONLY examples to explain things, without being able to explain things directly and clearly up-front.
To help explain things clearly, students should consider to adopt the top-down way. More details can be found in my earlier post on "Advice to Students on Mastering Communication Skills"
In a one-on-one meeting with me, when a student explains an approach in a paper to me, it is better for the student to use the top-down way. The student needs to first explain the problem being addressed by the approach. To help accomplish this goal, besides the direct description of the problem, the student could explain the inputs to the approach and the outputs of the approach, without first getting into details how the approach does it. A common pitfall for students is that students tend to immediately explain what the approach actually does without first giving me any ideas on what problem the approach targets at or what the high level inputs/outputs of the approach are.