You can be fabulous and frugal by mixing high and low fashion

Even if you can't afford designer clothes, Obama's fast-fashion skirts, sheaths and dresses accessorized with a belt or cardigan show how you don't have to spend lots of money to look good.

It also goes back to staying true to a style that fits her body and lifestyle, whether she's stepping out of Air Force One in a Target dress or making a grand entrance in a floor-length gown at a White House state dinner.

"She looks equally well-dressed whether she's in Target or a Talbot sheath or Michael Kors," said Taylor. "I don't know any other first lady you could see on TV one day and buy (what she wore) in a store the next."

Part of what makes Michelle Obama so relatable is that she wears designer clothes but mixes them with pieces from J. Crew and other mall outlets, often in the same outfit, said Chernikoff of Fashionista.com.

"That's an easy takeaway for all of us -- buy the Calvin Klein skirt and wear it with a Gap sweater," she said.

Build a timeless wardrobe of signature pieces so you can shop your closet

The first lady is known for working the same dress, skirt or cardigan on multiple occasions by mixing and matching pieces, Taylor said. She achieves this by building a bankable wardrobe of flared pants, pencil skirts and cardigans that work for her in a pinch, freeing her from the need to follow trends.

"Being comfortable in your own skin is not about following trends but setting them," Taylor said. "A woman who knows how to dress well shows wisdom and restraint and doesn't give into the fashion insecurity of thinking you need a new dress for each season."

True, much of Michelle Obama's wardrobe consists of expensive, quality designer clothing. But spending more on items made to last can cost less over time and reinforce the idea of developing a sense of style and staying true to it, said Spinelli of Savannah College of Art and Design.

"The idea of disposable fashion is costing us more than we know, so it's not a bad thing to teach people to buy something good and keep it for a while instead of throwing it out."

Don't be afraid of color and print as long as you have a deliberate point of view

Obama has embraced mixed patterns, textures and vivid colors, but her confident fashion sense allows her to mix it up with authority.

By wearing watercolor sheaths under embellished cardigans to talk to schoolchildren about healthy eating, or textured floral dresses to meet heads of state, she shows that it's not frivolous to express yourself through fashion while doing the serious work of the first lady of the United States

"She shows us that you can have fun getting dressed up and still be taken seriously and move issues forward," Chernikoff said.