This article was stolen from here: http://www.gq.com/how-to/fashion/200705/how-to-perfect-business-wardrobe
Shoulders: The suit's shoulders should hug yours. The shoulder pads should not protrude beyond your own shoulders. Chest: You should be able to easily button the jacket without it straining. Conversely, there shouldn't be too much space between the button and your chest—no more than a fist's worth. Length: When your arms are hanging straight down, you should be able to cup your fingers under the sides of your suit jacket. However, these days, with shorter suits in style, some jackets reach only about an inch or two beyond the cuff of your suit sleeve.
The three-button suit became the dominant look in the 1990s; it now seems to be the standard young man's choice. Instead of opting for one of those high-cut versions, look for one with a roll-over lapel—one in which you button the middle button, encouraging the soft lapel to roll over the top button.
For years the two-button suit was the go-to conservative, Capitol Hill getup. Now every fashion label imaginable is designing two-button suits, except they're making them more streamlined and modern. This cut is what's most in style right now—and it's the most versatile, looking good on almost every body type.
If you're looking for something rakish, a bit more high-style, try a one-button suit. It's not for everyone, but if you can pull it off, it's a sleek look.
A center vent is all-purpose; it is both modern and traditional. You can't go wrong. Side vents are more European, a bit more suave. They also add a little more shape to your suit. A ventless jacket, by the way, is a definite no. It says you think it's still 1986.
A notch lapel—what you see on most business suits—is the standard. You're always safe with a notch lapel. Go for one on the narrow side, which will have a more modern, slimming effect
A peak lapel is more old-school and elegant. And now it's enjoying a comeback with high-fashion and business crowds alike. It makes a statement. Just don't get them too wide—you don't want to look like a Sopranos extra.
Cap-Toe: You need at least one pair of slim black lace-ups for your business wardrobe. They work with every imaginable suit. Try these—the cap-toe detailing strikes a classic, professional look. You should also own a pair of brown lace-ups, but when it comes to those, remember this basic rule: Brown shoes work with everything except a black suit.
Plain Toe: If you want something sharper and sleeker, go with a slim plain-toed lace-up. It's dressier than a cap-toe and can be worn with a tuxedo to formal events. But you can also wear it on the weekend with jeans and a blazer.
Wingtip: The ultimate business shoe. Its intricate old-school detailing signals maturity and prestige. And don't worry about looking too banker-like—wingtips are back in fashion these days.
Loafer: A dressier version of these casual classics adds flair to your wardrobe. In the warmer months, try them with a khaki business suit. And if you're feeling adventurous, go sockless.
Opt for over-the-calf ribbed business socks. You don't want to show any leg when seated. Don't get carried away with bold colors or patterns—keep it classic. And match the color of your socks with your suit, not your shoes.
A cotton pocket square can add a dash of elegance to a business suit. Just keep it simple: Stay away from patterned silk ones, and wear yours square, not puffy or multipeaked. And never buy a matching tie-and-pocket-square set.
Like pant cuffs, belts are a personal preference. Slimmer suits or trousers with side tabs don't require a belt. If you are going to wear a belt, keep it slim and tasteful for the office. And generally speaking, it's preferable to match your belt to your shoes when dressing for business.
You'll need these when wearing a dressy French-cuff shirt. Just choose ones that are tasteful and refined—you don't want to be too flashy. And no, your links don't need to match your watch.
As we've insisted all along, less is more. Nothing should attract a disproportionate amount of attention—you want a clean, balanced, and classic look. All of these timeless watches will help you strike precisely that. They're slim, and they fit right under the cuff of your dress shirt.