I do things one room at a time. It doesn't matter if it's cleaning or decorating. I do make a list of what I feel needs to be done in each room and then when I get to that room I do what is on the list and if I find something that wasn't on the list I take care of that too. I also make a list for shopping and just get a few things when I'm out, online shopping has helped me out a lot. I can check the boxes once the kids are down for the night.
I also make a list of things for DH and the kids to do one weekend and we all get busy and do our list. This works if the kids are old enough to read. When they were little I would just tell them little jobs they could do to help out.