Listen to it
Accept or decline it
The one thing I've learned from entering my work in contests and online critiques is I have to be able to accept criticism. Its hard. It feels like being told I'm a bad mother. But after the the sting of the suggestions settle a little, I realize that some of them make sense, and when I re-work it, and what I end up with is a better story or letter.
Because, honestly, that's what I want, right?