I have bathroom cleaner, loo stuff, rubber gloves etc. in all the loos/bathrooms which means i walk past, see the devastation that DCs have wrought and can sort it immediately (I also clean the loo with loo roll so can immediately flush away)
Never open post unless you have time to deal with it (recycle/shred/sort)
Empty school bags/packed lunch boxes the minute they are within my grasp
I seldom manage this but when I have making a loaf's (or 2) worth of ham/choc spread/cheese/salami sandwiches on Sunday eve and freezing them makes life wonderful. I also freeze mini muffins for lunchboxes..they are unfrozen by lunchtime.
have 2 sports kit drawstring bags for each child (there are many) one for indoor PE one for outdoor and wash dry and repack as soon as used ditto for swimming gear.
Always cook double or triple and freeze some in family portions and some in individuals (if you dont have enough plastic you can tip individual portions out into a large freezer bag together once frozen).
Squeegee and spray the shower immediately after use. Spray bath with watered down washing up liquid immediately and shower down (cheap and clean).
Store clothes in "outfits" rather than types (top, trousers and jumper together rather than all trousers together etc.)
Keep spare/extra things where you use them rather in separate distant storage.
Give yourself a break occasionally....being too organised/clean/sorted is exhausting!!