In these 20 minutes, you will start with the part of your house that annoyed you in the first place. You know, part that you looked at and it just made you angry. Start with that.
Go to that place and start organizing your stuff into four bins: Keep, Unsure, Donate and Throwaway. Keep doing this for about 10 minutes.
Do not take out more stuff than you can handle in 20 minutes.
Now put the Keep stuff back. Move the donate stuff to a safe place. And split the Unsure stuff into Donate or throwaway. If you were not sure of keeping it, you do not need it and these things are causing the clutter around your home.
Now I am a messy person. I have to use this time to declutter because I accumulate stuff very quickly. Whenever I clear out my table, I go find new stuff to make it messy again.
Things become worse when I wire wrap, this is only one side of my workspace. It is filled with the tools that I am using. The other side is worse. I cannot work in messy conditions, in fact I become so annoyed that I end up trying to clean my entire house. This means that I waste a lot of time.