A long, flowy dress or skirt with wedge sandals works well, but add closed-toe pumps and a formal hair-do and you’re not casual enough. Jeans are great with stiletto heels and a dressy top, but these accessories are too formal if you’re wearing a pencil skirt.
Keep make up and hair fairly simple. An updo is okay with some wispy locks floating down, or stick with a simple ponytail at the nape of the neck.
Make up can rely on a palette of evening colors, but if you play up the eyes, leave the lips nearly natural, or pair red lipstick with very subtle eye make up.