Until the kids go to school, the only stuff you'll bother with is quick and/or long-lasting, so: if there's one thing you can invest time/money in, make it a good cut'n'colour that needs minimal styling. Mine just needs a comb-through when it's wet, dries naturally, and then gets backcombed and put up in a pony. I hope it's Catherine Deneurve, but I suspect it's more Amy Winehouse.
Shower: mix together sugar and olive oil in a jar, and use to simultaneously exfoliate and moisturise in the shower. Shave yr armpits, get out the shower, apply Dove or Johnson's holiday glow tanning cream.
Eyes: home-tint yr eyelashes (black) and eyebrows (whatever matches your hair). Saves so much time - you can basically apply lipgloss and blush and walk out the door. I pluck my eyebrows while the kids are in the bath - you're in the bathroom, bored, with tweezers. Might as well multi-task.
Do manicure/pedicure whilst watching the telly. Gold toes go with pretty much everything, and are very "2007", which I am reliably informed is what this year is.
Clothes: buy dresses. Spend all your money on dresses. They instantly made you look smart, even if it's just a £12 wrap from New Look with a nice pair of sandals and a necklace.
That said, I think anyone with a child below the age of three is allowed to leave the house wrapped in a duvet, with egg in their hair, and be met with nothing but murmurs of "Oh, you look fabulous."