If you're not naturally tidy, it's worth looking around every evening just to tidy up a bit - dirty cups in kitchen, pick up clothes of floor/put away jumpers left on sofas etc.
You will also require a Bowl Of Crap and a Pile Of Crap. Bowl of crap is to put stuff like keys, hairbands, spare batteries and other assorted crap that appears and you don't know where to put it. When Bowl of Crap is full, go through it and chuck stuff out. Pile of Crap is for opened letters, stuff from school, etc that you can't throw out just yet. When it gets big enough that it falls over, sit down and go through everything and chuck stuff out. 
I had to stop doing "clean as you go" as I could never sit down and relax unless everything was spotless. Personally I prefer a timetable.
(For the record I have no DC yet...)
Twice weekly: Change sheets (yes i'm a slattern! Would change them weekly if I had a big stinky man in with me
).
Weekly:
Clean bathroom (wipe down, sink, bath, clean loo - incuding wiping it all down including the handle.)
Dust everywhere - surfaces, light fittings, skirting boards, top of pictures etc.
Hoover everywhere.
Mop the places that look like they need it (kitchen, and hall usually, will do other areas if haven't for a few weeks.)
Clean kitchen sink.
Daily:
Wash up (check flat for coffee cups etc), wipe down kitchen surfaces, wipe down cooker if used. Wipe messy fingerprints off cupboard doors (ony an issue if anyone else has been in there!).
Anything else - as I go. Windows about once a year
.