A good explanation becomes shorter without becoming less true.

Revision usually improves accuracy rather than reducing it. As you cut, you find the qualifications that were doing nothing, the examples that repeated each other, the phrasing that was hiding a vagueness. The shorter version ends up more precise because the compression forced you to decide what you actually meant. Length and truth are not related in the way people assume.

Rewrite something you have already written, aiming for two thirds the length. Check that nothing true was lost. If it was, put that back and cut elsewhere.