Have a yearly “review” right before school year. Raise allowance as appropriate. If they want more money, they’ll have to take on more responsibilities.
Take the family on periodic “spending fasts.”
As an exercise, go a day, a weekend or a week without spending any money. Make due with what you have.
Encourage participation. Tie in spending fasts with holidays, lent or in support of a cause.
Don’t have a clue? (Relationships / career / character, etc.) The solutions can be found in books. READ! Novels, biographies, history, religion, humor, politics, finance, sports, and whatever sparks your interests at the moment!) You’ll learn about the world, and you’ll learn about yourself. READ!!!! (or listen!)
There are things you should not say:
Never comment or ask a woman about her age or weight.
Never comment on how many kids someone has (or doesn’t have.) The size, timing, composition, etc of someone else’s family is not your business to weigh in on. You never know who is struggling with loss or infertility, etc. And if someone announces they are expecting their seventh kid, the only correct response is “Congratulations” “How are you feeling?” etc. Just like you would if it was their first. Never ask someone how much weight they lost. If they’ve lost weight, just say “You look wonderful/amazing/ fantastic, etc.” And of course never comment on anyone having gained weight. Just say “You look wonderful.” And never never never ask someone how much money they earn or how much money they have, or how much they owe or paid for something, etc. People’s finances are personal, and are just not any of your business.
There’s always a temptation to throw money at your problem. But remember there’s nothing you can buy that will make up for what is really needed. And the stuff that accumulates while you try to fix the problem just ends up being a problem on its own.
Start “home economics” school with them. Laundry, cleaning, cooking, how to change a diaper, comfort a baby, soothe a toddler, what's involved in caring for pets, budgeting for food, keeping track of maintenance schedules for humans, pets, cars and machines. Engage with guests, be a good host, etc. Know when and how to tell someone to GTFO of the house (racist or misogynistic speech, etc.) Every kid needs to learn the art and science of home management. Look for and point out examples in books and movies of good home science skills.
I once asked my mom if my grandmother (her mother in law) was rich. Her reply: “No, but she likes to think she is.” I think she meant my grandmother spent money like she had plenty of it when she really did not. Can relate. I hope you do better!
Start saving money early. Save as much as you can.
There are plenty of things worth spending your money on, but be mindful about your money - Don’t p*ss it away.