You definitely can make a HUGE difference to your own life and that of your children and grandchildren. (But yes it won't make a difference to the decline of western civilisation.)
Stay out of debt - this is vital. If your can't pay for it, do without.
Reduce your mortgage by downsizing.
Whether you have a mortgage or rent, consider moving to where housing costs are cheaper and find a job in that area, instead of finding the job you want then paying a higher cost to stay near the job. Whatever you do, cut out the long commute.
If you have a second earner and two cars, switch one of the jobs to within walking distance of home, or on a bus route, and get rid of the second car.
Grow food, especially expensive stuff like salad leaves, tomatoes, etc.
Consider very, VERY carefully if it is worth your teenager going to university. Seriously, universities are a racket designed to keep middle managers and administrators employed, and the whole system will implode in coming decades.
Don't let your children have false expectations of their future - especially beware the narrative that secondary schools feed them, 'if you do well in your GCSE's you will get a good job'.
Hope this gives you some ideas.