From left: What I Wore, Ballantine Books | photos & sketches courtesy of What I Wore.

We have a total girl-crush on Jessica Quirk. Jessica's like that friend everyone has who can easily mix her Target with her Tory Burch, and can whip up a gorgeous outfit with only bare-bones basics (think a plain white T-shirt and a full skirt). When we ran into her at her most recent book signing --at SoHo's trendy DKNY store -- Quirk was wearing a lacy LBD, and well, it made us want to be friends with her even more.

Rather than keep all of her style expertise to herself, the blogger behind the wildly popular What I Wore is imparting some of her best fashion advice in her new book -- aptly titled, What I Wore. With her beautiful illustrations lining the pages (you may have seen them recently in InStyle & Glamour), Quirk covers nearly every sartorial question or dilemma ever had.

Need to know how to dress for work in 90 degree weather? Jessica has the answer. Or, if you're looking for a checklist of seasonal must-haves, Quirk's got you covered. We caught up with the busy blogger, and she dished on everything from her favorite jams to her fall fashion predictions. And check out our gallery below to see Jessica's favorite outfits that she's ever worn.

StyleList: What celebrity would you love to style, and what would you dress them in?
Jessica Quirk: I don't think she needs any help with her personal style, but I would love to swap closets with Zooey Deschanel! She does such a great job of mixing vintage and modern, and always looks adorable and quirky.

StyleList: What is your favorite fashion decade/era, and why?
JQ: I cannot pick one! I love vintage and I'd consider myself somewhat of a time traveler with my closet. It really depends on my mood. In the past I've done some seriously '50s and '70s inspired looks, and I just helped clean out an estate full of dry cleaned, mint condition clothes from the '60s (in my size! life doesn't get sweeter than that!) I've always loved history and it makes me so happy to dip into the past with how I get dressed now.

StyleList: What fall fashion trend are you most excited to try?
JQ: I'm keeping my eyes peeled for cute, childish prints made grown-up in great fabrics. Think little elephants, foxes and giraffes on blouses and dresses. I am crazy about anything with a fox on it.

StyleList: What is the best fashion/styling advice you've ever received?
JQ: Isn't the best style advice a little cliché? Don't let the clothes wear you. You're never fully dressed without a smile. Those are two of my favorites. I like to tell women that when you look good, you feel good. Wear what makes YOU happy. Not every trend needs to be for every woman.

StyleList: What song is on repeat right now on your IPod?
JQ: Oooh. I just charged my iPod for a long flight (for the first time in a long time), so I listened to some of my old favorites (Vampire Weekend, Mumford and Sons). I also recently got a free digital download when I bought the new Fleet Foxes LP "Helplessness Blues". I love the title track. It's about a young person finding his/her way. Do I want to fit in? Stand out? Who knows. I can absolutely relate.