Informal, Semi-formal, or After Five Attire for women is as follows

If it is an evening event, go with a cocktail dress or elegant separates. If it is a daytime semi-formal event, wear a knee-high dress, a dress suit or dressy separates.

Cocktail attire can be the most fun of all the dress codes and it doesn't have to cost a fortune. Here are some rules to follow.  Knee-length or tasteful short dresses can be paired with sexy sandals or ty tailored trousers beaded shells or silky tube top or shell.  You can throw on your LBD (Little Black Dress) and add fun hosiery, or a vintage broach or event faux-fur wrap.  Simple jewelry is fine, leave the jewel-intensive stuff for ore formal events.