I have always found that I am much better when I am in the right mood to do it. Like being made to write christmas thankyou letters on the day after boxing day, they were a real struggle to think of things to say, but when I wanted to write I could easily find things to say.
So, I have separate things. I will have a bit of a sort out each week, but that is more putting things back where they belong, and sorting mostly the kitchen out. But in the meantime I make sure I have a good amount of boxes and bags at the ready and then on a day I am physically a bit better and can move about more easily I start with a drawer. That doesnt take too long to sort out, and you then have that to look at and remind you that you have sorted something out so that is a plus. That is a quick and easy thing to do, so then while I can face it I then go to one of the hardest cupboards or set of shelves, and make a start there. Sometimes I dont even finish all of that most difficult place, but deliberately put into a plastic bag anything not sorted out properly, so that I dont allow myself to put the muddle back. Then the next time I am in the right mood I can finish that bag off and it is encouraging to see that bit done and it then seems less difficult to carry on with that room. Once I have done a room, I sort of allow myself a week off, just doing ordinary things until I gather up the energy and resolve to start again in another room.