With more users gaining rep to suggest and make edits, I thought it would be useful to gather some tips for editing questions. Our questions should be viewed like nuggets of gold - they are what keep great people coming back to the site and encourage quality posts all round! Editing is encouraged to get a little more shine out of a post, and approved edits even gain rep.
Please feel free to add to the c-wiki answer below or write your own answer if you have enough to say on the topic.
(Note - while related, this is not "how to ask questions". For that, read a great post on the Super User blog.)