I especially agree with the part about moving on. Once you've dealt with it, don't keep apologizing or bringing it up in later posts.

Another question is whether you should even approve some negative comments. When I first started blogging, I had this feeling that it was wrong to delete any comments. But that I realized that's a stupid idealist attitude leftover from the days when blogging was new and people had all these ideas that blogs should be completely open for all to say whatever they wanted.

But if you think of your blog as a business, or part of a business, that's ridiculous. If letting a negative comment through helps you by showing that you're open to other points of view, or allows you to make a point in response, then do it. If in some way it harms your business, delete it. You own your blog, nobody else does.