Ever wonder if you should wear those shoes with that dress, or worry that you won't make a good impression in that outfit?
You're not the only one.
Titled "Oh No She Didn't: The Top 100 Style Mistakes Women Make and How to Avoid Them," the book takes aim at fashion offenders including scuffed heels, socks with sandals, holiday sweaters and too much cleavage at work.
Click HERE to read an excerpt from Kelly's book.
Kelly identified four big fashion mistakes:
Style mistake: Mom Jeans. A mom jean refers to denim pants that are high-waisted, with a light wash and lots of room in the rear.
The solution: Upgrade to a darker wash jean. Regarding fit, if you're not broader in the mid-section, the waist should hit two finger-widths beneath your belly button. If you're bulky around the middle, the waist should hit you at your belly button.
You may have to try on a lot of jeans to find the right pair. Kelly said the average person on "What Not to Wear" tries 20 pairs of jeans.
Click HERE to see Clinton Kelly's three web-extra fashion mistakes.
Style mistake: Turtlenecks. If you have a larger bust or you want to look thinner, beware turtlenecks. They add bulk to the chest and minimize your neck. That's a problem because your neck is the most important body part to show off if you want to create a thinner, taller silhouette.
The solution: A V-neck de-emphasizes the bust and draws attention to the neck, making it appear longer and creating a slimmer look.
Style mistake: Misguided belt. A belt is the first thing people notice. If you are wearing one around your lumpiest area, the eye will be drawn to that area.
The solution: Put the belt around the slimmest parts of your body to draw the eye there. A belt should be proportional to size, so people who are larger should wear a thicker belt. Slimmer people should wear a thinner belt. Anything thicker will overpower them.
Style mistake: Cross trainers. This has become the casual footwear of America, and it sets the wrong tone, sending the message that the wearers don't care about their appearance.
The solution: There are so many ways to be both comfortable and stylish. You can wear non-athletic sneakers, sandals for warmer climates, flat boots in the winter or ballet flats for anything.
The problem: Lame little black dress. Not all black dresses are created equal. Showing up at the event in a shapeless black sheath won't cut it.
The solution: The LBD should be classic -- so it won't look dated year after year -- and chic, so you can dress it down for the day and up for the evening.
The problem: The Boca sandal. In his book, Kelly writes that these sandals -- a white sandal with a low, square-heeled sandal -- seem to be worn most by women in Boca Raton, Fla.
The solution: Flat, strappy sandals are better than a Boca sandal.
The problem: Matchy-matchy outfits. In his book, Kelly says matching what you're wearing on top to what's on the bottom appears out of date.
The solution: Technically, any color goes with a neutral. Neutrals are black, gray, navy, brown, khaki and white. All neutrals go together. But some color and neutral combinations are not such a good idea. Black and orange might suggest Halloween, for example, while red and green definitely say Christmas.