No matter our best intentions, it seems the rooms in our house inevitably get cluttered up - things get dumped in corners, drawers or under beds, and if we're not careful they can stay there indefinitely, building up until one day we look at the room and suddenly realise it's a mess.
I have found that if I designate one room a month to focus on, although it seems like little enough, with the realities of every day life it's a realistic goal to do over a couple of weekends and it generally helps to keep the house looking orderly and decluttered. It also feels great to donate or throw away things that when you ask yourself, you really don't need it any longer - it refreshes the soul somehow :)
So I've created a simple printable that allows us to designate one room a month to focus on, and some check offs to make sure we thoroughly declutter and clean.