Guys: Here Is Why Your Clothes Don't Fit

• Pinch just an inch. When it comes to how shirts fit on the body, pants drape against the thigh, or jackets shape at the waist, if you can pinch more than an inch, keep going down a size until you can't.
• A fitted well-shaped suit will make you appear taller, leaner, more confident. Seeing your reflection might even improve your posture. But rarely does an off-the-rack suit fit perfectly. Use a tailor. Patronize stores that have one on the premises. For updating the clothes in your closet, find a tailor in your neighborhood. Tailoring is not nearly as expensive as you think. Many dry cleaners have one on site. Whatever the extra cost, the results are undeniably worth it.

• If a jacket doesn't fit in the shoulders, don't buy it, because you can't fix it. And if it's in your closet, give it away. It's doing you no favors.
• Most men look best in two-button suits. Double-breasted suits have had a big comeback and can sure be dashing. But you can NEVER wear the jacket open. For that matter, if you are standing up, it's best to keep any jacket buttoned, unless you are thin. An open one adds about 10 pounds to your silhouette.
• Can you find your waist? Good. Well, that's about where you wear your suit and dress pants, as well as chinos. If your middle is larger than you would like, you can go a bit lower, but pants still have to close higher than your hipbone.
• Your pants should stay put without the need of a belt. If they don't, they're too big. Take them in.
• Unless you are preparing to smuggle in your emotional support Chihuahua in your pant legs, fabric should gently hug the top of your butt, graze your thigh and taper slightly as it falls from knee to ankle. If you are more heavyset, then let the leg fall straight from the knee.

• Pants can have no break, or just a slight one at the ankle. Skip cuffs. What's the point? Plus, they shorten your leg. And no pleats, please.
• Jeans call for a different fit. They should rise a little lower and definitely be tighter. Yes, tighter. At this point in life's trajectory, don't you dare wear your jeans low. You don't look cool; just foolish and sloppy. It is not too late to look sexy and sleek. Let people see your rear. Frankly, it's the best reason for wearing jeans. And speaking of looking foolish and sloppy — no acid wash, no holes, dark wash only. Looking pulled together in jeans is a big plus.
• If you are tucking your button-down shirt in your pants the same way you make a bed, it's not the shirt for you. Remember, only tuck one inch. If you are in trim in the middle, look for those labeled “tapered fit.” Shirt cuffs should stop at the lowest bone on your thumb, and protrude about 1/2 inch from your suit sleeve.
• For shirts, trust cotton: easiest to launder, most comfortable to wear. Silk can be alluring but it's also really warm. Linen looks a mess in an hour.
• In fact, don't wear linen ANYTHING. Europeans seem to pull off the wrinkled look better than Americans. (Perhaps we are too obsessed with ironing.) But fitted men's clothes in linen make you hesitate to move, sit or eat.

• Pick a classic collar, or one that doesn't shorten your neck. Your collar button should close easily. If you think ties choke you, you're wrong. It's not the tie. It's your shirt that doesn't fit.
• T-shirts and sweaters shouldn't be cut like tote bags. Both should have some tapering.
• With sweaters you want comfort, not bulk. Cotton is a great choice for summer. A soft wool (not Shetland: too itchy) for winter. If you can afford cashmere, it offers warmth without weight and feels really good. (However, Uniqlo sells cashmere pullovers in the fall for under $100.)
• Your fitness will influence T-shirt selection. However, sleeves shouldn't flap away from your arm, graphic designs rarely enhance your torso, and wearing witty slogans is funny for about 30 seconds — the first time. Choose solid color cotton tees. Pima cotton makes all the difference. They cost a little more, about $30, but try one from either A/X Armani or Mack Weldon and you'll immediately understand the recommendation.

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• If you shop online, it's best to opt for sites that have brick and mortar extensions.

Cashmere sweaters on display at Uniqlo.

Bloomberg/Getty Images

For example, Bonobos is an excellent online destination, but it has outlets where you can go in, work with a knowledgeable staff who can find your most flattering sizes, and then you're set because sizing is consistent throughout their line. For suits, Suit Supply is such a godsend, it's the sartorially suave Tim Gunn's go-to place for tailored clothing. Italian fabrics crafted in China keep the suit costs reasonable, sizing is across-the-board stable and the tailoring is excellent. Club Monaco and Hugo Boss are go-to brands, too.

Big splurge tip: For those who really want to do it up right, Suit Supply also produces made-to-measure suits for 25 percent the price of what luxury brands charge. I promise, the result is so wonderfully self-congratulatory, no one may see you in dad jeans ever again.

Hal Rubenstein is a founding editor of InStyle and former restaurant critic for New York magazine. He is the author of five books, including 100 Unforgettable Dresses.