Simply tax all income the same ~ at the lowest rate with the greatest number of deductions, exceptions, exemptions and credits.
Do that and you’ll be heavily taxing anyone who decides to invest, rather than consume, their income after they’ve already paid taxes on it.
On the other hand, anyone who spends all of their income doesn’t have to pay any more than any sales taxes for spending it all.
That is a major tax hit on those who would do what is better for our economy—and manifestly unfair.