Here is an example of what a finished "set" looks like on Polyvore. This whole set is made from clothes and accessories that I actually own, but you can always put together a set with anything you like:)
Once you have created a set you can add it to a collection, so for example I have a collection called "Back to School 2012" which has multiple sets in it. You can have as many sets and collections as you want. :)
Polyvore is a great way to organize and create different outfits from the clothes you already own. And I's also a really great way to gain inspiration for future shopping trips and outfits you ordinarily wouldn't have thought of on your own. I personally have found it to be very useful while back to school shopping. There are so many ideas on Polyvore!
You can follow me on Polyvore, my username is: teenagefashionista
Enjoy, and let me know what you think!