Here is a link to a New York Times article with tips on how to save for college:
https://www.nytimes.com/interactive/2018/business/how-to-save-for-college.html
(Note: It is a long article with many parts to it. Keep reading past the ads that interrupt the text.)
Seems like a simpler solution for most of the forum demographic (top ~10% income) is to live substantially below your income.
For example, if your income is $150k, live like your income is $100k or less. If your income is $200k or $300k, live like your income is $125k or less. Note that these levels of living are by no means “poor” even in expensive areas (where the median household income is that much or less).
Given that the economy is trending in ways that increase the pass through of economic risks to labor (as opposed to capital, which absorbed a greater share of economic risk a generation or few ago), resulting in a large percentage of households having negative income shocks (e.g. laid off from job, extended unemployment, can only find new job at lower income), it is prudent to avoid depending on all of your income to live, and a good idea save at a high rate to join the capitalist class as soon as possible.
^^^ Prudent, but easier said than done.