Meal plan. It is tedious planning, but in the long run it does save both time and money. I have menus on a four week rotation split into each season based on what we all like.
A slow cooker is a life saver.
Batch cook and have a few nice ready meals in the freezer.
Have 5 sets of school uniform and 1 spare set for each child.
I make a batch of sandwiches for the children's packed lunches on a Sunday and freeze. Take out night before or morning and are defrosted for lunch. Add salad in a container, as you cannot freeze salad.
Clean as you go Less to do at weekend.
Laundry one load on as soon as you get up. Hang up to dry or tumble dry as soon as you or partner get home.
Have a drawer with assorted birthday cards, stamps, gift vouchers, sellotape, batteries of various sizes, pens, spare hair bobbles/slides, mini hairbrush, envelopes and £30 made up of £1 or £2 coins. This has saved my arse many times when the children have needed money for a cake sale, non uniform day etc. Also when I have forgotten a birthday!
Saturdays in this house for food are treat days. This is when the children can choose what they want to eat within reason. Bakery treats for breakfast/brunch, Mcdonalds or a take away for dinner. Saves my sanity.
Have a dedicated work bag with all the stuff you need in it for the working day. Keep it stocked and check monthly so you are ready to go in the morning and don't have to faff around on a work morning. Keep it in one place. Mine is by front door.
Time yourself getting ready in the morning if you have a tight deadline to be out of the house. I allow 30 mins for shower, teeth, dressing and breakfast. This does not include getting children washed, dressed and out.