How to get long hair to hold its shape throughout the day?

I have really long hair(it stops a little past the top of my butt). the strands themselves are fine, but i have a lot of them, so my hairs pretty thick in the sense that it has some nice, medium sized full layers. i recently just had layers cut in. and the 2 hairstyles i love are volume and curls. all curls, messy sleek, or even just some wave.my hair is naturally straight, so i really want to give my hair some body and movement, not just straight. one of the problems that i run into though, is that because my hair is so long, my hair cant seem to keep the shape. keeping volume isn't as big a problem, it lasts pretty well. but even with the layers, which does make my hair lighter, my hair is still a bit heavy. is there any trick i can do or a really great finishing spray or just fabulous product that will allow me to keep my wave and movement through out the day(with out making my hair feel like i just dumped a bottle of Elmer's in it) ?