Personally I break down tasks into stages so that I can jump between tasks but still get stuff done.
I pick a room at a time, make a list of the things that need doing in that room only and cycle through the tasks. When I do a room I take a bin bag, cleaning supplies, a donation box and the washing basket (for items that dont live in that room) with me. I also keep a notebook for any random other jobs I remember and then just put on a podcast/music and crack on.
I just cleared out DDs room this weekend. I managed to go through 3 podcasts and an audio book but her room is spotless ... the rest of the house is a bombsite still, but that is one room done.
Before I did anything else I set a 5 minute timer and took a bin bag and did a quick sweep of big/obvious rubbish (sweet wrappers, packaging from new stuff she got at Christmas etc) to get it out of the way and stop me getting distracted by it at the later stages. Then I set a 10 minute timer and did another sweep of things that didnt live in her room and dumped them in the washing basket to be dealt with later (if I left the room to start putting those things away there and then I knew I'd get distracted, so instead I just corral them in a specific spot in the room.
Then anything on the floor/lying around got put on her bed because I find that the things we have lying around are the things we use most and they are usually lying around because we cant find space to put them away because our cupboards are full of stuff we dont need. This means that I always start jobs by doing cupboards/drawers first and then once the unused stuff is gone there is usually room for all the stuff that was previously lying around.
I needed to sort through her clothes and accessories - checking sizes, removing Christmas bits, weeding out worn out items, weeding out things she never wears etc. So I pulled everything ou of her wardrobe, set a 20 min timer and then handled every item once and tried to make myself make a quick decision - if it was still good it went back in the wardrobe, if it was worn out/damaged it went in the bin bag, if it was too small/not worn but still good then it went in for donation, if it was out of season then it went into a pile to be put in the box of out of season stuff I keep in the loft.
Then she has a kallax unit which houses all of her toys, games and books so I basically designated a certain number of cubes for each category, set the timer and again sorted through everything with the one touch method - books she reads or are new went back on the shelves, damaged ones went in the bin, ones shes grown out of went in the donation pile etc, same with toys and games.
I just continued around the room with each area, dividing into tasks and setting timers till I was left with a washing basket full of stuff for the rest of the house, a couple of binbags of rubbish, a big bag of donations and one of stuff to go into the loft.