The biggest impact has been to have a goal of limiting a paragraph to 2-3 sentences. From this goal my other writing traits came naturally.
When starting a paragraph, start off with a blunt statement that summarizes the paragraph. Following sentences can back up the summary sentence.
Use a short single-sentence paragraph to make an emphatic point.
Do word qualifiers add to your content? Many times not. Humans add qualifiers and adjectives more than what's necessary to understand a concept.
Readers get bored with monotony. If there's a wall of text, that's boring. If there's a wall of images, that's boring too. I try to break up a document into different types of formatting. Lists, headings, quotes, and image/content sections to make things visually appealing.
These are only goals! Sometimes a big honkin' paragraph is just what the doctor ordered.
Fun language or a well-timed joke keeps things interesting. They can give the reader a well-deserved break. Like the big honkin' paragraph usage above.
Lastly, the presentation of the content is important. Medium got their content width, font size, and colors down well. GitHub did a great job, too.
I learned to do this when a publisher took red ink to a tutorial I wrote. They gave me the goal of shortening all paragraphs to 2-3 sentences. It was tough at first but now I'm a fan. It's a fun writing exercise :-)