You are only allowed to buy one new roll of wrapping paper per year. You just got pink Tinkerbell wrapping paper on clearance. You are not allowed to buy any more for next Christmas. And you probably made Baby Jesus cry with that particular choice.
Prioritize teaching your children to give to others. Adopt one of those needy kids/family paper thingies from the tree in the supermarket. Have your children pick out the items for them and help drop them off. Also investigate whether they're old enough to volunteer for Toys for Tots or a similar program. Remember about this before the third week of December.
Require the girls to clean out their toys before they can receive more. I know, you hated doing this as a kid yourself, but you're still failing to do it for them as an adult and teaching your children that they MUST KEEP EVERYTHING. While you're at it, clean out your own stuff as well....
Figure out a budget for presents before you figure out what toys you want to get them, and make the toys fit the budget. And don't do it the other way around like you did this year. Pricing out how much you think the stuff you want to get them will cost and then saying you're underbudget because you stayed under your initial guesstimate does not count.
Take each of the girls to pick out a present for their sister. You should have started doing this two years ago, now stop being a lazy bum and make the effort to take each of them out shopping one day by themselves in the month of December. It won't kill you, really.
Bake more Christmas cookies/fudge/treats. BEFORE Christmas. Also involve your children more. I know, sugar cookies with them this year was an exhausting event with marginal results. But come on, they're not going to learn if you don't teach them. And if they don't learn, they can't make you delicious peppermint fudge in a few years.
Make gifts for the grandparents with the girls. If you need to do this in September to
get it done, so be it. Paper cut out mittens never go out of season when properly sprinkled with love and glitter.
Remind people at work that you worked Black Friday Open, Black Friday Close, Christmas Eve Close, and 4am on the 26th of December AND the 1st of January this past year. You earned selfishly picking which holidays you want off this upcoming holiday season. So take them.
Watch more holiday specials. Sure they get cheesy after a while, but a little classic Grinch cartoon goes a long ways in making it feel like a special season. Even when you're all grown up and cynical of the idea of any special magic associated with any specific day on the calender.