First, make sure whatever you are going to wear is weather and location appropriate!
Pick one thing you definitely want to wear. It doesn't have to be clothes; it could even be a necklace or a pair of shoes! I really want to wear this skirt so I chose it.
Pair your item with a shirt (or bottoms or both, depending on what your item is) that doesn't match but GOES with your item. I'll explain matching and going in another guide.
Add a pop of color, whether its jewelry or shoes or a scarf!
Pair it with casual shoes (I love my Toms!) and you're ready to go!!