There's an interview with Tina Fey in this month's Reader's Digest. A couple of excerpts:
RD: How do you deal with it if you must write some comedy material and you're just not feeling funny?
Fey: I put on an I Love Lucy costume [laughs].

RD: Today's comics seem a little more type A, a little less self-destructive, than the previous generation. Why do you think that is?
Fey: There have always been different types of people if you look at great comedians. You have John Belushi and Richard Pryor, who lived dangerously. Then you have Jerry Seinfeld and Bob Newhart, who are happily married, mild-mannered guys. And their humor doesn't come from a place where they need to almost die to make comedy.
RD: It seems like you fit in the latter category, that you're well-adjusted.
Fey: Yeah, I think so. Jerry Seinfeld once said you don't have to be crazy to make comedy. To make comedy, maybe you just have to work hard and be funny.