First, you need several boxes. Label them; "need to keep," "garbage," "donate," and "emotional attachment." If the space you are clearing stores seasonal items like Christmas decorations, having a specified box for seasonal items would be a good idea.
So then you open up this drawer, closet, nook, whatever it is that needs to be taken care of and start sorting! If it is an item the you use often, then put it in the "need to keep" box. If it is trash, put it in the garbage one. If it is the watch you have had since you were three years old that does not work but you just have to keep it because it is so special to you, put it in the "emotional attachment" box. And then if there is anything that you are willing to part with, that is still usable, put it in the "donate" box.
Now is the easy part. Take the "need to keep" box, and put everything back in the drawer or closet in an orderly fashion, put the "garbage" box in the garbage, take the "donate" box to D.I. (really, do it then or it will sit around cluttering up your space for ever!), and then get some tape. Seal up the "emotional attachment" box, put it on the top shelf of your closet, and five months later, throw it out! Do NOT open it up and look in it, just throw it out. If you didn't grab anything in there in five months, you can definitely live without it.
There is my tip for you! Happy de-junking! It really makes home a better place!