You don't need a lot of clothes to look great every day. Streamlining your wardrobe to only the clothes you'll actually wear will, in fact, save you time and stress. Here are some suggestions for both men and women for the main necessities.
Apartment Geeks offers these suggestions for women, based on The Pocket Stylist: a nice dress, two jackets, three skirts, three sweaters, two dark trousers, two jeans, three coats, a white button down shirt and a few t-shirts should be flexible enough for both casual and dressier occasions. (Of course, you can add in shorts or substitute a blouse for the button down if that's your style.)
The suggestions are pretty similar for guys in this infographic from Lifestyle by PS (mentioned in passing in our how to build a budget work wardrobe post), which adds accessories like belts and ties. Again, tweak to your lifestyle, since not everyone would consider bow ties or tuxedos clothing essentials:
Upgrade by downsizing!