* If you put it away in the fridge or freezer, please label it, even if you're absolutely sure you'll eat it tomorrow.
* If you open something marked "use or freeze by [date]", please make sure that if it isn't used by that date, it gets frozen. (If you want to play it absolutely safe, freeze it right away; this is not ideal but is definitely better than throwing out something that's been left in the fridge longer than it should have been.)
* Please don't put dirty dishes over by the dishrack. It gets exceedingly confusing in very short order. Dirty dishes go in or to the right side of the sink.
* Dishes piling up in the sink appears inevitable until we get the much-heralded dishwasher. Therefore, please try to make sure that there is at least enough room under the tap for someone to get a glass of water.
* Please rinse out--or, where applicable, fill with water and leave to soak--dirty plates, bowls, pans, etc. Please do NOT leave wooden utensils or sharp cutting implements in standing water.
* If it has a colored label and you finish it, please replace it as soon as possible. If it doesn't have a colored label and you finish it, please put it on the shopping list.
* Please remember that the cat loves to nibble on leftovers that may or may not be good for him, and will happily knock over a glass to get at water in the bottom; compost anything that doesn't get refrigerated, and empty glasses in the sink before leaving them on the wash-me side of the counter.
* If you wash and dry it, please fold it. Please don't leave it in the dryer for someone else to find and wrestle with. Please, please don't leave it heaped on the dryer or folding table where it will get knocked onto the litterbox and need to get washed all over again. This goes double for small items like socks and underwear. If you're really in a rush, at least toss those into the blue basket under the clothes rack.
* Please don't leave wet towels sitting on floors, beds, etc. Hang them up in the bathroom or put them in the hot wash hamper (closest to the stairs) downstairs.
* If a kitchen towel gets clumps of food or food-related material stuck to it, please extricate and compost them before tossing the towel into the hot wash hamper.
* If you see that the upstairs hamper is full, please distribute its contents among the hampers downstairs. This will also ensure that its contents get washed sooner.
That's all off the top of my head, but I'm sure the other locals could probably think of a few to contribute. What are the rules of your house?