The hardest part is just getting started, isn't it? It feels so overwhelming...
I would suggest you start with the most public room. Just pick one and start in one corner and work your way around the room clockwise. But set some ground rules for yourself.
1) Take before pictures. Yes, I know they can be absolutely horrible, but you know what, you'll be so glad you did it when you are done and you can see the amazing progress.
2) Set a timer... Commit to working on the room for at least fifteen minutes every day, perhaps longer if you can.
3) Touch each item once as much as possible. That means that you decide when you pick it up where it will be permanently stored or you will donate it or throw it out. The exception to the touch it once is things going elsewhere. I usually make a pile or use a laundry basket to designate things for other floors. One of the best descriptions I ever read about clutter was that it was a decision delayed.
4) Start small. You can always do more later! That means, start by working on one shelf, clearing one chair, clearing one table at a time. Don't jump around the room or sort things into smaller piles. Don't start on a second shelf until the first shelf (and everything related to it - like putting things into other rooms, taking the garbage out to the garbage can, etc.) is done. Be brutal and realistic about what you are keeping. When is the last time you used it? Would you REALLY miss it if it was gone? If you had a fire, would you replace it? How hard is it to get again if you decide you do want it in the future?
(Some people think it is better to pull all the stuff (EVERYTHING) out of the room and then sort it into piles and put things back in an orderly fashion. While I think this is fabulous if it works for you, I don't think most of us have the space or time to do this. So instead, we end up pulling things out in the room and put them into smaller piles. So at the end of the day, it looks like we have made no progress because we all we have is a 100 smaller piles of crap).
5) Just do it! As you make progress, it will spur you on to doing more.
Don't forget to take in progress and after pictures to track your progress! :)
