The main rule - clothes for corporate parties should not be artsy, provocative. Your choice - elegance, not a challenge. Think of a party with colleagues as a kind of continuation of the office. Adhere to the "golden mean" - hide behind gray low-key things too to anything. Your view should match the theme and atmosphere of a party, wherever it took place - in a restaurant, bowling or in the office in the evening after work. If you are invited along with her husband, allowed an open evening dress, but if the presence of the second half is not provided - Dress modestly. Boss can afford more expensive and bright toilet, than subordinates. If the invitation for the evening dress code is specified, it must match.
The best option - is, of course, the dress. Be appropriate neutral colors - pastel colors, black, silver gray, chocolate, they look at the same time solemn and quiet. Fabric's better to be easy - then you will not be hot. Diagonal lines cut look stylish and unusual. Add originality draperies, oblique bottom, cutout on the back, not the chest. Trousers and top or jacket will also work if the party is less formal and solemn character. Carefully selected and stylish accessories will give your whole look of completeness. Do not be amiss to remind that the abundance of jewelry is not appropriate anywhere, let alone at a dinner with colleagues; limit to one, at most two ornaments: an elegant pendant on a chain, bracelet or earrings.
If the party is supposed to right in the office after work, and you can not change clothes - a bright accent revive even the most modest attire. Neckerchief, a flower barrette or trendy colored top coat under strict attract attention, but not caught my eye.
Fashionable and elegant, but at the same time discreet and feminine look to add your credibility in the eyes and subordinates, and superiors.