Put away, throw away, give away.
Any successful purging of 'things' begins with the three aways. It's best to set up boxes, bags, totes, baskets...etc that you can put items into easily. When purging an area, set your holders close by so as you pick up an item, it can either be put directly away or put into one of your holders. Once your area is purged, it is then time to deal with your holders.
Obviously the throw away is the easiest, so go ahead and get it out of the way.
The give away then needs to be determined if it is to be given away to a specific person or is it being donated to a thrift store, church, needed organization. Organize into where it is going, and then make arrangements to get it there. Set a limit on how long your stuff will sit before it is delivered. It doesn't do much good to purge an area only to have piles of 'things' sitting around.
The put away is where you need to be very careful. It's easy to put this stuff somewhere just to be done with it, only to have to purge the same items more than once. Take the extra time and put things in their proper places.
Once all your aways have been taken care of, stand back and admire your work. Even if the whole rest of the house seems to be falling down around your ears, take pride in what you have accomplished!
Remember, your areas needing purging didn't get the way they are overnight. Don't put the unrealistic expectation on yourself of getting it all done at once. Take your time, enjoy the purge. That's right, take satisfaction in the job you are doing, know when it is done, you will be a less cluttered self.