Clutter busting is like sweeping your floor. You sweep because dust and dirt has accumulated. When you're done the floor looks clean and you feel better. You clutter bust because you have accumulated things that are not a part of your life anymore. When you're finished your living space looks good and you enjoy being in it.
Here's something you can do right now. Stay where you are and take a look around at your immediate surroundings. If you're sitting at your desk let you eyes scan the surface. If you're sitting on your couch see the things in the room you're in. In the same way you would notice dirt or trash on the floor, see if you can spot things that you just don't use anymore. What jumps out? Maybe it's something that you used to use a lot and now you're tired of it. You'll know the feeling. You'll have a knowing sensation, "Yes, that's clutter."
Now in the same way you would sweep up dirt you see on the floor, take these items that are of no more use to you and put them in a bag. If it's trash, throw the bag out. If it can be donated take it to a charity place. It helps to remove them from your environment now so you can start enjoying your living space right away. A good feeling is worth the effort.