Another one who does everything the night before apart from making up sandwiches and chopping fruit and veg, which I do as soon as I get up. The DC pack their school bags before they go to bed. I write notes for the teacher, sort out money and sign forms as soon as get in from school or activities. I lay out lunch boxes on the kitchen counter and put in all the non-fridge items.
I set aside a couple of hours in the week before school starts (next week in fact) to go through absolutely everything that the children need in terms of uniform, pencil cases, shoes etc and label them. I use mynametags and get it all done in one job lot. Then it's put away ready for the start of school.
I make up a weekly schedule for each child with their music practise, homework and other extras that fits around their Afterschool activities and this is on the kitchen notice board. This works for the whole term and means that the children can look for themselves to see what they need to do after school.
I have a list of 30 meals that everyone will eat and meal plan for the week. This allows a bit of variety but doesn't tax my brain too much. I know that I have something for dinner each night and I take the relevant ingredients out of the freezer before we leave for school. I have a one in use and one spare system for just about everything so we rarely run out of things. I really think this makes a difference as there is no last minute panic about toothpaste/shampoo/juice boxes (obviously the latter is a pack rather than individual) and no expensive 'pop to the supermarket' bills. Anytime we start on the spare, it goes straight onto the shopping list that hangs by the fridge.
I use an Organised Mum Family Life Book and everything goes in it ASAP. This means no double-bookings and lots of planning time for birthday presents or costumes. I put a note in a week (or however long you need) before to post or buy gifts. I bulk buy birthday cards in August and then use a folder to put specific ones away ready for that person's birthday. I have a box of spares, including wrapping paper and gift bags.
I have a weekly list of cleaning jobs, somewhat like Fly Lady and just work my way through that. Little and often in the cleaning department (my least favourite part of my routine).
I find that all of this planning means a smoother time at home. Then I have plenty of time to help with homework or listen to music practise even if I'm tired after work and running the DC around.