Now that I have you surrounded by massive piles, it's time to purge. And yes, you do have to purge. If you had enough room for everything then you wouldn't have had to organize.
I've always called these the purging rules, but they are more like questions you should ask yourself.

1. Is it broken, unusable, or worn-out?
After you've "used it up and worn it out", you're supposed to throw it out. We expect our kids to let go of these kinds of beyond-repair items...so we have to set a good example and let go of ours.

2. Do I have enough of this item already.
I have seen some crazy collections of grocery sacks and the like. You need to ask yourself: Will there ever be a situation when I'm going to need 30 empty butter containers?

3. Would I pay a storage fee for this?
On one of the organizing shows, I heard the organizer say that if we are not using our rooms for living space, then our mortgage is just a storage fee. I really liked how thought provoking that was. So if most of your rooms are filled with clutter and are unusable, ask if you would pay a storage fee (as high as your mortgage) for these items.

4. Does this represent who I am today?
We are not our possessions.
Our actions represent who we are, not our clutter. Do we hold on to things because we think they represent us-- or once did?

5. Does this invoke happy or sad memories?
After my mom's death in '01, we had to clean out her house and decide what to keep. My mother was a collector, so there was plenty to spread around to her nine children and then some.
When choosing which items to take, I realized that if I chose things on the basis of: "I remember this was always on Mama's dresser" or "Mom really loved this" then every time I looked at it, it would remind me that my mother was no longer here to enjoy it.
So instead, I chose things that were pretty, or that would look great amongst my things. So now, when I look at these objects, I am happy. I can think, "Look at this beautiful object....I got it from my mother".
Our loved ones do not wish for us to be sad or to live our lives for them. They want us to be happy, safe, and fulfilled.

I don't think there's much room left, so I will stop here....but there are eight more questions so keep reading.