A properly fitting bra can make or break an outfit. But understanding sizing, the relationship between band and cup sizes and sorting through the array of available bra styles can be overwhelming. Good thing the Twin Cities area is home to fitting experts, including Tracy Anderson, who owns La Bratique in Edina. We asked Anderson to share her brassiere-based knowledge.

Q What is the most common mistake women make when selecting a bra?

A Purchasing a cup size that is too small and a band size that is too big.

Q Which is more important, band or cup?

A Eighty percent of the support comes from the band, so that's the most important part of the bra.

Most women have a distorted sense of what a D cup looks like -- they think Dolly Parton or Kim Kardashian. So they select a cup size they think might be more appropriate for their figure.

Forget about cup size and focus on band size. You may end up in two or three different sizes, depending on the brand and fit, vs. just one cup and band size.

Q Define a properly fitting bra.

A The band should be snug and sit parallel to or lower than the front center of your bra. The wire should sit directly under the breast and just behind the outer tissue. The front underwire should sit flat against your sternum. It shouldn't poke out or sit on top of your breast tissue. You should be able to slide your finger between your bra strap and your shoulder. The straps shouldn't be doing the heavy lifting, but should be tight enough so it doesn't fall down.

Q How can you tell if a bra doesn't fit well?

A A bra cup is too small if you have any breast tissue spilling out the front, bottom or side of the cup.

If you have to tighten your straps to create support or lift, you're wearing the wrong size. Lift and support must come from the band, so if you're making the straps too tight, try a bigger cup and a smaller band.

If your straps fall down or your breast tissue falls out of the bottom of the bra, you need a smaller band size and/or a bigger cup.

If there's a gap between your breast and the bra cup, the cup is built too big for your frame. You most likely need a smaller band and/or a smaller cup.

Q Is there a proper way to put a bra on?

A I recommend leaning slightly forward and scooping your tissue in from the side and bottom, and then gently shaking your tissue into the bottom of the cup to fill it completely. Make sure to get all of your tissue to fit into the cup so the underwire doesn't rub on the sides.

Q What is the relationship between cup size and band size?

A The cup and band size are built in proportion to a woman's frame. This means that the cup of a 32C is one cup size smaller than a 34C cup, even though they are both called C cups.

When you go down in band size, you go up in cup size, so a 34C is same size cup as a 32D. However, the 32D is built deeper, so the breast can naturally fall forward, while the 34C's cup space is built wider.

If you're wearing a 34C, but your actual size is a 32D, you'll be spreading your tissue wider, creating more gap in your bra cup, and losing the ability to properly define your bust.

Q Are there certain styles that can help avoid the dreaded "back fat"?

A Just choosing a bigger band won't reduce back bulge. What you need to remember is that a bra is meant to support the bust, taking weight off the shoulders and back. In order for a bra to do its job, it must hug the body and feel somewhat snug. A band that is hugging the body actually reduces back bulges because it will sit lower on the back, where we naturally have less fat.

Q Can a bra change the look of your body, even under clothes?

A A bra can change a woman's silhouette in minutes.

The softer the bra fabric, the more natural the shape. But while softer bras may feel comfortable, they can allow the breasts to droop or push to the sides of the body in a way that creates a heavier look. Softer fabrics also have more stretch, which means they wear out more quickly.

Stiffer fabrics provide more shaping and lift. Many women avoid molded cups, fearing they will make their breasts appear larger. But if the fit is right, molded cups can lift breasts off the torso, giving you a longer, leaner silhouette.

Q Why are minimizers so popular?

A In the U.S. market, we have been led to believe that full-busted women should wear minimizing bras, but that isn't always the case. A minimizer can push the breast tissue toward your armpits and flatten your breast to your torso, which can make you look heavier, broader and bustier.

Sally McGraw is the Minneapolis-based author of Already Pretty (www.alreadypretty.com), a daily blog about the intersection of style and body image.