I teach secondary English & have 3dc aged 9, 8 & 6. I've always taught FT; from what I see of PT it's 80% of the work for 60% of the pay...
I do one 'througher' every three weeks or so when I put the kids to bed on Saturday evening & work through until morning on planning & resources - not for everyone, I know.
Also, because dh works away, I have a PT nanny (we have dc at the same school) who dovetails neatly & flexibly round my hours, which is absolutely invaluable - if you can find someone who'll do this, life becomes so much easier.
Batch cook, have a big freezer, & get organised with meal planning. I spend a couple of days every holiday filling the freezer so if I know I'll be arriving home just as kids are starving, I can take a tub of chilli/bolog out of the freezer in the morning & just do rice/pasta when I get in. Also, there's nothing wrong with beans/eggs on toast for tea when you've forgotten to do the above.
I know some people work through lunch, but I can't - if I don't have one break during the day, coming home & immediately starting the Mum Shift totally outfaces me.
Oh, & establish a mindless, bedtime-ish TV programme (mine is Emmerdale) as your absolute unmissable favourite. Insist that you are sat on your bum in peace watching this whilst your partner does whichever part of the routine you'd be up to by then. Don't let yourself do any marking, planning, or open your work email until after this watershed! 