The article below is from http://www.fhm.com. After all my research for a quick ‘go-to’ guide, this is the best article to go by…
Donning a suit can be a risky business. Avoid these schoolboy errors to look the part when you’re going smart
Mismatched collar and tie size
The trend for skinny ties involves shirts with pointed collars. The wide cutaway collar that is currently very popular requires a chunkier tie and a larger knot like a Windsor, not the half-Windsor as shown.
(For a knot tying guide that correlates with collar types, Email: firstname.lastname@example.org to get a free instruction guide)
This isn’t the 1980s – shoulder pads should always sit directly on top of your shoulders and finish above your shoulder’s end. A jacket that is too large will swamp your frame, giving it little definition and making an expensive suit look cheap; a poor fit is why politicians often look bad in designer tailoring.
The point of the tie should just touch the top of the belt – and never hang further south. Practicality means you don’t want the tie flapping around and getting in the way when you go to the bathroom; psychology means you don’t want something shaped like an arrow pointing at your cock.
The darker brown leather is mismatched with paler shoes. The belt is also made from distressed leather, which is too scruffy and casual to be worn with a suit. Tailoring should be about clean lines. (And remember: women are like hawks when it comes to noticing details.)
The hem needs to brush the heel of the shoe and sit on the upper around the third lace. While there is an emerging trend for rising hemlines and ankle-cut trousers, you have to be very “experimental” to pull it off. This length falls between the two, making you look like a schoolboy after his growth spurt. Socks should only be visible when seated, never when standing.
Only use your suit’s inside pocket and even then not for anything heavier than notes and credit cards. If the outer pockets are stitched shut, leave them so. Keys, wallets, phones and iPods distort the line of the jacket, pull on the buttons and shoulders, and stretch the fabric.
The sock should match the shade of the suit or be darker, which will help to make the leg appear longer. Patterned socks can be fine, but only if the background shade is the same tone as the suit, or the same tone as your shoes. Otherwise it’s akin to novelty tie wearing: drawing attention to your questionable taste in accessories.
Footwear should be of the same tone as the suit or slightly darker, like the socks, to elongate the leg. Light tan with a dark suit is too big a contrast and can make your feet look enormous as well as risking you looking “footballer at awards ceremony”.
Check out the full article here