Clear the clutter! Go through each room and collect a bag of things to donate, and bag of things to throw away. If you have cabinets and drawers, use them to store the things you want to keep (but don't really need to look at). It makes it much easier to keep clean - just a quick swipe and the surface is clean again.
Especially in the kitchen - having things permanently out on the side means they build up a layer of sticky grime that attracts dust and makes it harder to keep clean.
Put EVERYTHING away in the cupboard/on shelves. At most, have your microwave, toaster and kettle out, but don't fill up the surfaces with sauces, oil, pots of utensils, etc. Maybe I am militant about this because I have such a tiny kitchen, but I do not allow ANYTHING to live on the work surfaces. My boyfriend seems to think the ketchup lives on the work surface, pushed to the back. IT DOESN'T :)
ETA: get rid of things you've been "meaning to get round to fixing" if that time frame is more than six months. I recently donated a load of blankets I'd been saving with the vague idea of turning into a patchwork quilt, and a "really useful" load of cardboard boxes, and a box of attachments from the mixer I inherited from my nan. I didn't need any of it - someone else can make use of them, but it isn't going to be me.