Have a place for everything, when you are finished with soemthing put it away.
Don't leave a room after making a mess,
i.e. if you've made a sandwich for lunch and the bread/knife/butter/ham are out, put them away, if there are crumbs on the bread board, wipe it down, wash up the knife you used. Then go and eat your lunch. When your lunch is finished, wipe up your plate. Voila, no mess whereas you could make the sandwich, leave everything out, plan on doing it all once it's finished, but get called away for something else and your kitchen is going to stay a mess. Do the same with dinner, if you're dishing up, have a sink ready and wash pans as you go along, before you sit down, then all that's left is plates for afterwards.
Tidy all rooms before bed.
Have a basket in the hall for things that don't belong downstairs (ours is on the telephone table) and when it gets full, put it away.
Delegate, give DC's and partners jobs to do whilst you do something else.
Have a full on hour after dinner, when one person cleans up downstairs, and another does upstairs and bathtime.
Have one day a week where you gut a room.
Don't sit for too long. If you're on MN, give yourself a limit, i.e. 5 threads, then I'll do something useful, or if watching the TV, this programme then do something, reading, four chapters then do something.
Have plenty of storage, baskets are fab. In my kitchen cupboard there are three baskets, one for bits n bobs(batteries/washing line/odd screws), one for medicine/first aid kit, one for clothes/dusters/scourers