Read! Your writing skill will usually trail your reading proficiency.<p>If you mean business correspondence, find a nice book on professional communication (which may have to be adapted a little for modernity.)<p>Here’s the balance: less words more concise (unambiguous) meaning. Don’t meander. Use bullet point structure if you must. Try to supply necessary details you think others will require without round trips.<p>It’s okay to write an email, and come back in some time and reread it before sending. Self editing is like good hygiene!