Took it in turns with DH to have a morning to myself. Even if it is one weekend morning a fortnight or a month, just to know if was coming!
Took a morning/afternoon off work once in a while to get on top of things.
Paid for extra childcare at a time when I wasn’t doing any work. We had a nanny, so she did overtime, but I know that nursery workers do this, or babysitters or whatever. Pricey, but sometimes needs must.
Delegate what you can, and pay for that, if you can afford it.
Best thing overall for me though was to have early nights. And then I’d feel more on control of everything. I wasn’t more in control, but I did feel that I was! If your children sleep in, you could get up early having had proper rest, and use the time for whatever it is you want to do, or do nothing. This doesn’t apply if you have an exceptionally early riser child like mine though!