Do you look like a mutton dressed like a lamb?

Or have you given in to frumpiness?

Whether you’re a mom with a toddler or teenager, a woman going through a midlife crisis, newly single, or moving into menopause, your clothes can make a difference in your life, according to British fashion and BBC television journalists Trinny Woodall and Susannah Constantine’s new book, “What You Wear Can Change Your Life” (Riverhead, $22).

The 263-page book offers no-nonsense, honest advice about how women can best dress to suit their figures. The women, who host the British hit television series “What Not to Wear” (and before this wrote two other bestselling books, “What Not to Wear” and “What Not to Wear on Every Occasion”), said their experiences have helped them understand how important looking good – and feeling that you are looking good – is to a woman at any stage of her life.

According to the book, at midlife, don’t dress too young or too old for your age. And at menopause, don’t give up. Using themselves as models (they swear none of the photos in the book were touched up), the women suggest “repackaging” to hide body flaws ranging from sagging upper arms to thickening waists.

“There is a lot of fear that you need quite a lot of money to buy a nose job or a new wardrobe to look good,” but by using this book, you find this isn’t true, Ms. Woodall said in a telephone interview from London.

Trinny and Susannah – as they refer to themselves throughout the book – urge women to begin by doing something most women would rather not do: stand in front of a mirror naked.

“It took us a long time to realize the importance of body assessment,” they write in the book. “What we conveniently forgot was the fact that our bodies had changed over the years. Fad diets, pregnancy, exercise, and lack of it had left us with bodies we no longer recognized. Because the changes happened slowly, we weren’t aware that our figures were no longer lithe and lean, and consequently, we were buying all the wrong clothes …Only when you accept your body shape will you have the courage to move on.” Moving on starts with correcting one big mistake for most women, Ms. Woodall said. “Most women wear the wrong bra size,” she said. “[Studies have shown] 70% of women wear the wrong-sized bra.” The book devotes an entire chapter to underwear and its importance. “If you are a human and female, you will have a graying white cotton, fraying elastic, skin-digging wire poking out from bras….These cannot stay…. What you require, girls is SUPPORT and SHAPING in all areas that have given in to gravity.”

They give tips on everything from the importance of harnessing large breasts to reining in flabby stomachs.

“Anyone from a D cup upward must realize that a well-fitted bra is the most important item in her wardrobe,” the book says. “Don’t be scared of spending three times as much as you would expect because you will not regret it.” For those with the opposite problem, they suggest “the universally great bra for the flat-chested has to be the Wonderbra.”

Some other tips covered in the book include how to build a no-cost wardrobe:

Invite a bunch of girlfriends over and tell them to bring a selection of their clothes that they no longer wear. “Every woman has screaming mistakes in her wardrobe that she tries to ignore by pushing them into the back recesses, where they fester in the vain hope of being worn. It’s never going to happen, so appease your guilt, and get rid of them NOW.”

On makeup: “The trouble is that we get into a routine, and it sticks. Our eyelids might droop, our hair color might change and the wrinkles get deeper, but still we put on that heavy black kohl for the panda-eyes look.”

Women who wear too much mascara: “Why, we ask ourselves, do they do this? Of course, the eyes are the mirror to the soul, but how the hell are you supposed to look in when they are curtained by thick, black, hairy spiders’ legs?

Finally, “If you’ve worn the same makeup for the last five years, it’s time to re-evaluate.”