The following photos show off super casual updos. What they all seem to have in common, aside from the fact that I think they look good because I never, ever include hairstyles I hate in my image galleries, is that they all seem to have texture to them, usually in the form of waves or curls.
To get your hair in tip-top updo shape, you need to make your hair texturized in some way, so you hair doesn't slip out of its updo. To do this, you'll need some sort of styling spray, perhaps dry shampoo and a lot of pins and hairspray.
This style on Brooklyn Decker is gorgeous because of that texture. In real life, she often goes out and about with super straight hair, so some work went into getting her hair super beachy and wavy for this look. Note also her gorgeous hair color.
This is Gallery 1. See my other galleries of mussy prom hairstyles: