When you're in the sorting process (the crucial first step) of organizing a specific room, STAY in the room for the organizing session. (Prepare for the session by having trash bags on hand for trash, recycling, donations.) Invariably you'll find objects that actually do have a home in another room or on another floor. Most of our clients, if left to their own devices, are inclined to leave the room immediately every time they come across an object like this to return it to its home. And in the process, it's REALLY easy to get distracted and to not return to organizing.
Instead, use some boxes or just make piles if necessary, that you earmark for specific rooms. For example, you might have a "goes in bedroom" pile, a "goes in office" pile, and so on. As you organize the space you're working on, just put the object in the proper box or pile. Then, as your energy for organizing dwindles but BEFORE it crashes entirely, take your piles or bins to the earmarked rooms to put things away.
Not only does this technique decrease the chances for distraction, it also simply saves time because you're not making multiple trips to the same destination.
The only exception to this rule is if there are some really large objects in the room you're working on. If you can immediately clear large bulky objects (e.g. a bike) from the space that you're working on, you not only create more room for your sorting, you will see an immediate change in the space, which will create a sense of progress. The perception of progress is one of the biggest motivators to keep going.
How do you organize? Do you tend to leave the room each time you encounter something or do you practice stockpiling and THEN putting things away once you've reached a critical mass? (Image: Flickr member Nstohlma licensed under Creative Commons)