The most traditional option for a wedding cocktails attire suit, which is to say, that being jackets, trousers, and optional waistcoat are all cut from matching fabric, is in a medium gray color. Off course, going for something even darker such as charcoal, gray or navy blue is also perfectly acceptable. Because of its historical associations with country wear, brown suits should be reserved only for informal variations such as wedding cocktails on cocktail attire.
In such situations, you could go for something slightly bolder as well. For example, a burgundy or olive green and if choose one of these more Avante-garde colors, however, note that it should be dark and conservatively styled and most often, without a pattern. Conversely, A black suit would be much too somber for cocktail attire and should be avoided. Black to be the most overrated color in men’s wear.
No matter what the color of suit you choose, solid colors are safest. You can go with a faint pattern such as a light windowpane or maybe a Glenn check but keep in mind that the pattern should be conservative and not overly loud. As far as the styling of suit is concerned, you can go for single or double-breasted and two pieces or three. It is not entirely unheard of these days for men to be seen wearing combinations of sport coat or blazer and odd trousers at cocktail attire events. Although, we think it is still best to go for a traditional suit. To provide contrast with a more medium to dark suit then, your shirt should typically be lighter in color. White is a standard but you can also go for off-white or pastel colors like pink, yellow, or blue.
A Winchester shirt which is to say a shirt with a white collar and sometimes white cuffs, paired with a colored and occasionally patterned body, can also be an acceptable choice for cocktail attire so long as the color that is incorporated in the body of the shirt is similar light and subtle. Dark shirts or shirts in a jewel tones like burgundies, eggplants and so on, are too modern and too Avante-Garde for traditional cocktail attire. A subtle pattern can also be incorporated into the shirt though you should ideally opt for just one of these, the shirt or the suit, to have a pattern, not both at the same time. Barrel cuffs are a perfectly traditional and acceptable choice although if you opt for a shirt that has French cuffs to accommodate cufflinks, the links should also be understated.
Regarding ties, solid ties are a safe and acceptable choice but traditional patterns like small dots or micropatterns are also a smart choice. Just make sure you avoid anything too bold such as an oversized paisley, for instance, bow ties are a bit less commonly seen for cocktail attire. Smooth silk ties will be your safest option though you can opt for a bit of texture as well.
As such, remember to keep your outfits comfortably within this level of formality.