They understand that copy should be as short as it can be while properly conveying the desired meaning and tone. Experts hate waffle and padding.
They never write ambiguously, leaving the reader to scratch his or her head. This is especially so when producing instructions, directions or guidelines. The HELP sections of WordPress and Amazon are great examples of clear instructions.
Professionals understand that writing can be improved by leaving it in the computer and reworking it the following day. If they can put the writing aside for a week, so much the better.
Spell check makes stupid errors, often mistaking one word for another. That’s why the pros always proofread their work. Twice.
It’s easier to change copy than to write copy. Therefore giving it to five people to review will result in a mess that pleases nobody. One or two people is plenty.
Expert writers are nevertheless grateful when colleagues find mistakes and point them out. It’s better to have these corrected before the boss or a customer stumbles upon them.
They might be skilled at the written word, but they never criticise colleagues’ writing or make suggestions for improvement, unless asked to. You wouldn’t want these people denigrating your haircut or choice of shoes, no?
The pros are experienced enough to know that writer’s block is a form of stage fright. Starting a piece of writing can be hard. The longer you practice, the more your acquired skills will carry you through.