Define your drawings
Here’s a good idea: define and exaggerate the visual dynamics of your drawings and sketches, farther than you initially believe they need to be. An analogy to music performance is the need to always push acoustic dynamics further.
Even if they’re rough sketches, the client needs to be able to read the illustration and have a good sense for the aesthetic subtleties you’ll be using. You also may never know what their eyesight is like – just because it looks good to you doesn’t mean it’s getting the point across to someone else. How do you know when you’ve pushed contrast and tonality enough? A nice trick is to walk 20 feet away from your drawing. If contrast, lineweight, and dynamics are right, the main content, if not all details, should still be very visible. Simple but trustworthy.
What do you think?