Help!! How should wear my hair to a wedding?

Going to a wedding outdoors in the country. Im wearing a strapless knee length dress with a cardigan and cowboy boots. My hair is dark brown, medium length, straight, and sort of thin hair. Curls don't work with my hair. I don't want to wear it like i normally do. I want to look amazing. If I wear it totally straight it will get frizzy. Updos are usually hard for me to do. But if anyone has one that doesn't look messy and thats not to difficult that i can do that would be great.