Whenever I buy a new sewing pattern, I take one of my folders with only pockets inside, and I cut off the front of the pattern, and paste it to the front of my folder. This way, I can locate the pattern I am looking for when I thumb through my folders.
On the inside left--I place the guide sheet for the pattern. The inside right is useful for putting all of my cut up pattern pieces. I usually cut these out when I buy the pattern, so I don't have to come back and do it later. If I am unsure about sizing, I just leave it intact until I go to sew it.
Finally, on the back of the folder, I paste the information from the back of the pattern.
I really like this method because everything is in one compact folder, and I can put it all away easily for use the next time. The only space this takes up depends on where you store the folders. I have mine stacked for now, until I can put them in a drawer. I also love the pockets because there is extra room behind the side with the guide sheet, for storing any pattern modifications you made when you sewed the pattern.
I think I got these folders from Walmart, but just recently I couldn't find them, so I had to go to Office Depot.
Feel free to share how you store your patterns with me. I am still working on an outfit for my daughter. It's been slow-going, but I hope to have something to share with you all soon!