Ages ago there was a thread on the larger families board for sharing tips. Found it! really old thread, but really helpful
Washing is just constant in our house, twice a week (if I can) I throw it all in the front room on the rug and sit and watch TV while sorting it into piles, I creep into the DCs rooms and put it away at about 10/11 at night.
I do think you have to lower your standards, I have thrown an old sheet on the floor nest to the dryer in the (sort of) utility room, all clean dry washing get folded/throw on the pile until I have time to put it away. Often of a morning the DCs are getting dress from stuff I pull from the pile!
I never supermarket shop. Ocardo are amazing, I have had missing items once or twice over the few years that I have been using them. Baths/showers are only every other night.
Cooking is banned after school (war can break out in the time it takes to cut and onion or peel potatoes) so its all re-heats from the freezer during the week and pizza on Fridays (another tip stolen from the above thread). I have discovered frozen ready mashed potatoes, jars of sauce for bolognaise and even chopped frozen onions.
The slow cooker is amazing if you are in during the day and can throw stuff in at lunch time. I cook rice in the rice cooker (more revolutionary than it sounds, I used to ruin the rice because a nappy needed changing or i would put the rice on but not get dinner on in time).
I also always have a meal in the freezer, fish fingers, chips and frozen veg. If it all goes completely wrong I can fall back on that.
Best mantra on some days is 'All fed, none dead', this allows you to put them to bed un-bathed. I have wet wiped muddy feet before and packed them all off to bed because I was simply exhausted.
...sorry I have rambled on rather! It does get easier (in some ways) as they get bigger, 3 of mine are now big enough to be thrown out into the garden for the morning and can dress and feed themselves (and are potty trained) which makes thing much less arduous.