I think they are very important. I have a wonderful editor who allows me to choose from wonderful covers. Coming up with a title is always a challenge for me, but I never regret the ones I choose.
Yes. Another writer gave me some good advice: When you are blocked, leave that portion of the book to come back to later, and write another part of the book. It works for me.
Yes I do. Of course, I love good ones--especially if they see something about the story that I hadn't even realized. The bad ones I try to realize that not everyone likes the same writing style or topics, but if there is something in the criticism that helps me to improve my work, I try to keep that in mind.
I have written stories since I learned to print in elementary school. I took many creative writing classes in college and high school. When I became a copy editor I realized it was time to submit my own work, and here I am six years later.