It's about ruthless organization.
I work FT (but have been doing 4 days taking parental leave 1 day from Sept to the end of Jan - I have yet to have a day that seems "free"). DH works FT and up to Oct was doing 2 weeks out of 4 overseas. DD is in school too but I work in the city centre so she has to go to afterschool until I collect her at 6pm. (While DH was doing so much overseas travel, and it was 2 week long trips, we had an au pair for 3.5 years, but we're managing without one at the moment).
I meal plan. So I shop according to the list I have made of meals for the week and I always have a good handful of alternatives available for easy dinners when exhausted or "Mum I don't want that" nights, and takeaway numbers programmed into the phone for really bad nights (I rarely do chippy, but there's a good Indian and good Chinese nearby, and a Dominos, all of whom deliver if I am really wiped - Dominos and Indian are only 3 doors apart so DD can have pizza and I will have curry sometimes). So a well stocked freezer and pantry are always helpful too in reducing takeaway temptations.
I use internet shopping - not every single week but frequently. If I know a week is particularly busy, I will set up the shopping in advance. I will also try to have weeks that I only need a small shop, and use local stores rather than large supermarket (saves time and stress).
I organize meals so that I make a good dinner on Sundays, when I have time in the afternoon. I also make a dinner for Monday that is fast to just reheat (like curry sauce, chilli or spag bol - where I am just heating it and cooking rice/pasta) or cooking in the oven on timer when I get in (lasagna, cottage pie, fish pie, etc). The Monday dinner is always something freezeable so I do a double batch on the Sunday, and there is something for mid-week next week from the freezer too. It really works for me as Sundays are quieter - Saturdays could work too.
Tuesday is usually a chop or fresh meat/fish bought at the weekend. Wednesday/Thursday is a combo of freezer meals, relatively quick and easy to make meals (like curry using a jar instead of making the sauce from scratch, or a Chinese stiry fry) or convenience foods (oven chips and chicken kievs/battered fish/decent burgers, frozen pizza, a good ready meal etc). Friday is the night I am most likely to succumb to takeaway - but I often get an M&S meal as an alternative.
Saturday is a night that I tend to relax over cooking dinner and Sunday it all starts again.
I also try and prep ahead the night before. So after dinner, filling dishwasher and washup, while DD relaxes in front of tv before bedtime, I peel veg and potatoes for the following day, marinade meat if needed, take things from the freezer, set up the oven on the timer, .....all that sort of thing. And I make both DD and my lunches - I have a big salad, and she has all sorts except won't eat sandwiches. Set up the counter for breakfast - glasses, bowls, cartons of cereal etc all out - so it's ready to grab and run in the morning. And I can immediately turn around to cook when I get in the following evening rather than prepping first.
I keep on top of the washing of clothes during the week - I set the washing machine to run during the afternoon so I can take things out clean when I get home. Then they either go in tumble dryer or on the clothes horse (or even outdoors if weather allows) when I get a couple of minutes around making dinner or tidyup time. When clothes are dry, they go into a second laundry bin downstairs - which I only fold at the weekend (usually either DH does it while watching a Saturday evening movie with DD or I do it late on Saturday night when she's in bed and I am watching something). So we can rummage if we need to during the week, but I do tend to have a reasonably large wardrobe for everyone day-to-day so it's not necessary too often (DD doesn't have school uniform, so we have about 10 tracksuits as everyday wear - if she had a uniform, I'd have extra shirts and probably an extra skirt/trousers and jumper just in case). DH irons when he's at home.
I do the basics of housework as I go along - and DH does his fair share when at home. So sweep most days when tidying after dinner, keep counters clean as I go, pick up clutter as I move around the house. I do bathrooms at the weekend, mop using the steamer maybe once a week, change towels at the weekend, dust when it is needed. I have had periods of having cleaners in once a week/fortnight, and the au pairs did a certain amount of housework when they were there, but my aim is a generally clean and tidy house, not magazine show standard.
I keep the paperwork under control - I have a spreadsheet for budgeting and keep track of bills due in ahead of time on that. I pay bills the day they arrive - but may set those up on internet banking for anything within the next month (so I often set those for paydays) or immediately write a cheque and put it in the envelope - which I then leave in the hall to post on the day I need to. Notes from school are also dealt with on the day they come in.
We keep a small diary on the counter in the kitchen. It tracks DH's travels (and my occasional trips for work too). It reminds me of DD's activities (what days does she need extra gear, or extra snacks) and I write in everything to that as soon as we get it. Family appointments (doctor, dentist, school meetings....etc). Trips "down home" for the weekend to our parents. And plans for social things - cinema trips, planned concerts (including school concerts), potential outings that we can go on, or family dinners etc.
As soon as we get in at night, I turn on dinner, empty out bags of lunchboxes/notes and check homework (DD does most in afterschool club). DD now sets the table and is starting to lend a hand when asked. If I have time then, I will start putting laundry out to dry, making next day's lunches or prepping dinner, checking post, writing notes, paying bills etc. Or they may get left until after dinner.
It is exhausting. I have to make sure I give myself time to slow down. Like reading a book in bed, or retreating to bed with the iPad to watch something instead of settling on the sofa at 9.45pm (fine if earlier - but I am up early so go to bed at 10), or having a bath when I am overstressed. Watching that I don't get into a rut of bad food - so convenience food a couple of days is ok but remind myself to get back to plenty of veggies and healthy things again even if using a jar of sauce to bind it together.
DD does a lot of activities in school - there are different sports and other activities available in the afterschool programme so she does something every afternoon (her choice) - 3 sports, chess, and religion. Then goes to afterschool club where she gets a snack, does her homework, and plays until I get there. So we are not under too much pressure midweek to do other activities (we gave up swimming as it was too tricky to get to), but we have 2 different sports at the weekend, and are about to change 1 sport for Cub scouts (that I am becoming a leader for again) and add in sailing - which is great as it gives me 3 hours free!!
My current boss is not as understanding as the old one was if DD is sick - I have to take annual leave to mind her. We used to be able to juggle that we'd mind her a half day each (DH and I), with the other doing a long half at work (so going in at 7 until lunch, or lunch until maybe 7pm) and a couple of hours each at home after DD would be in bed - more or less getting a full day's work done. We don't really have family who can cover it due to distance - although 1 aunt of mine has now retired and also no longer cares for DGM so can do some if needed. But I tend to go in to work early and do evening collection, while DH sorts mornings at home and works later than me in evenings, on a daily basis. We also have a lady coming in for an hour in the mornings to mind DD and take her to school so we are both gone by 7.30am (need to commute 12km in city so 35 min cycle for DH and 20-60 mins for me by car/public transport depending on traffic and time of day, partly why I go early).