Poser is a 3d modeling tool that has a bunch of preset models such as people, animals, etc. For the advanced modeler, you can import your own stuff, but I'm not that advanced. When you are working with a model, you can 'pose' them however you want hence the name. The juggler figure was done in poser, then I exported him to a program called Bryce where I did the beach scene and the juggling balls. I rendered the picture in Bryce.

How would you suggest I compose it better?

Maybe to create a sense of movement, blur the spheres a bit