I know it's a big deal to get someone else to read my work and give me feedback on it. I value those individuals very highly, and I KNOW that I wouldn't be able to make my books what they need to be without their critiques. But there's more to getting and using feedback than just looking over my beta readers' notes.
First I have to make sure that I'm comfortable with the story. After all, I don't want to send out a book that more than likely undergo serious changes. Any improvements that I can make on my own are gotten out of the way before I seek help. This is also important because most of the people who do the critiquing don't have a lot of free time, so their probably only going to have the time to read through it once. I never want to waste their time and mine by giving them a version of the story that will provide useless notes.
When my critiquing friends are doing their work, I try to take time off... you know, play some video games, read a book or two, send out query letters... that kind of stuff.
Then I get the feedback notes! My first reaction (after biting back untrue comments about the reader's parentage) is to keep the notes in my e-mail folder until I actually sit down to edit. I'll glance over the notes now and then, but I like to tackle them one at a time, focusing on the areas the notes point out as problematic. I go through each one in order (I'm a little OCD that way), and sometimes I make several passes at each section to make sure I get it right.
I follow all of that up with my own read-through, making more edits as I go, and if I'm happy with the book, I start querying. Otherwise, I find more people willing to read through and give me more critique notes...and repeat the process.