If you have any decluttering tips to add, please post them here!
To declutter, you'll need at least 2 boxes and trash bags. One box is your Keep box, the other is your Donate. I'm a little embarassed to say I've had rooms completely stacked with stuff! I'm such a packrat and I'm always fighting against my natural tendency to keep things on the chance that "maybe" I'll need it.
Start from the doorway and work clockwise around the room. It gives you some order to your work rather than just randomly wandering through the room "cleaning". As you touch each item, put it where it belongs- Keep, Donate, or Trash. Try to make your decisions very quickly.
Automatically trash anything that is broken and either can't be fixed or that you haven't found time to fix in more than a month. You probably won't find time to fix it in the next month either. Before you keep something, ask yourself if you will use it in the next 6 months or if you have used it in the last 6 months. If not, donate or toss the item. If you are keeping an item but it belongs in a different room of the house, don't put it there right now. If you leave the room it's easy to get distracted by other things that need organized or done in other areas. Before you donate an item, ask yourself if you will *really* take it to goodwill or to your sister, or wherever your donations will go. If you won't take it in the next week, get rid of the item.
After you have divided the room up, take out the trash, and box up the donation items. Get them out of that room! Now sit down with all the items that you are keeping. Sort them by where each item belongs. When I did this I had a box for each of the other rooms of my house, so I could put things in the "kitchen" box or the "bedroom" box. When I was finished sorting I took that box to the right room.
Look through the items that you have decided to keep in that room. Do you *really* have room to store all that stuff in there? Look critically through those items and donate or trash more. Take time to thoroughly dust, vacuum, and clean while the room is clear.
Think through your storage needs. What needs to be stored in this room? How would you like to store it? What kinds of storage do you already have available to you? When I was doing a massive organizing project to turn my office into my son's room, I had zero storage for the new baby except for a dresser. So I made a list of what I needed to store (wipes, diapers, blankets, toys, etc.) and purchased storage that would fit those needs. Try to think about new ways to organize space- do you have a tiny room? Think vertical- wall-mounted shelves might be a great option for you. My son's room is very small, so as a solution to that we took the doors off of his closet and put a ton of shelving in. As a boy he needs very little hanging space, so I was able to use the shelves to store just about everything, including toys. Now his room feels a lot bigger because most of his things are stored in the closet. It's very easy for him to play in there because of the arrangement.
After you have purchased and/or set up your storage, put everything away. I know you're really tired right now, but don't skip this part! Put EVERYTHING away so that the room is truly finished. If there are items you just don't want to put away or don't have space for, re-evaluate those items. Do you really need them? Or are they more items for your donate box?
DECLUTTERING WITH LITTLE ONES
If you have kids who aren't in school yet you probably don't have a chance to spend 2 days straight decluttering a room... or 1 hour straight for that matter! My boys are currently 3 and 1, and it's a challenge to declutter with them around! We moved in April 2008 and I'm STILL trying to get things in some semblence of order 8 months later.
I try to spend 30 minutes a day in the room I'm currently working in, and I work like that until it's done, even if it takes several weeks. When my youngest was even younger I'd do 10 minutes, call it good enough, and do 10 more minutes the next day. It's not a very fast process, but every little bit does help. You won't be able to really tell a difference until a week later though!
My 1 year old's room is my current disaster. I've taken to doing my sorting and organizing with giant rubbermade totes. The thing I love about this is that when I'm done for the day I just snap the lids back on things and my son can't get into the things I've sorted. So even though this is a longer term project, I'm able to leave it out each day during the duration of the project without worrying that my son will undo all my hard work!