Work one room at a time. For large spaces, start even smaller with a closet or cluttered corner. Divide all the items into boxes or bins. Have a bin for keep, get rid of, and move to a new location. Once the area is completely cleaned up, replace the “keep” items in their place. Move the “new location” items to their new location.
If you are cleaning up to prepare your home for sale, you may need to package some of your belongings up for temporary storage. If you aren't moving, though, storage just results in more clutter you have to face eventually. Avoid storing items unless they are seasonal. The truth is that once something gets stored away, you will forget about it.
Once you are are done with the room by room decluttering, it's time to decide how to manage the “get rid of” items. Personally, I go through and label them all for a yard sale. A stick price tags on them and have them ready to go for when yard sale season starts in early summer. All I have to do on the big day is move them onto tables since they are already priced.
I always schedule a donation pickup for the morning after the sale. That way the clutter does not reenter my home. What ever doesn't sale is instead donated to my favorite charity.