I've been writing for DS since August..though not nearly as much any more due to the drop in price of suggested titles and the lack of doable provided titles.
Be straight to the point. If there is something you can say in five words instead of ten then do so.
Be clear..add pictures if it would make things easier to understand.
Their template is super easy. Just break everything down into small steps...start each step with action; think verbs.
Add some links and info to the tips area at the bottom.