Stick to formals. Especially meetings!
Choose quality and simple fabrics. Avoid linen because it easily wrinkles.
Avoid the trends. Flashy clothes tend to attract attention and distract many people. Choose clothing that is more sensible and toned down.
Watch footwear. Shoes should be polished, clean and not run down at the heels. People often judge others on the appearance and condition of footwear. Generally black shoes go best with blue or gray trousers whereas dark brown shoes match best with tan trousers.
As for colours, avoid bright ones. Formals are the best for work. Gray, blue and taupe are all excellent choices. Never combine more than two colors in one outfit.
Skirts should be kept at a moderate length. Women should realize that when they wear skirts too short, they may be unintentionally crossing the line between femininity and seductiveness.
Take your cues from upper management. Look around at how your bosses are dressed and follow their good example.