A basic one is negative gearing + trusts + cheap loans.

Negative gearing allows you to deduct/combine different income streams together to reduce your taxable income, and hence tax liability.

Traditionally used by middle/upper middle class to deduct mortgage interest payments and reduce their taxable income.

Rich(er) people combine this with trusts to distribute income/expenses among trust beneficiaries for something more tax advantageous. Usually this is someone like a spouse, child, or extended family member.

Add on the fact that rich people get cheaper loans, which often makes it cheaper to finance day to day life with loans, and only draw down (ie realise capital gains) after shuffling around incomes/expenses for a year.

Tax loopholes are basically legal ways to shift the timing and benefiary of income/expenses. There's a bunch of other ones, like

• choice of depreciation calculation
• purchasing things on behalf of a "trust" or "company"
• getting paid in low tax jurisdictions
• moving money into tax advantageous retirement accounts

Businesses. I've seen 'the back end' of an upper middle class family with a business, and the ways the mother (the tax genius of the scheme) moved money around and labeled various things as expenses for businesses was wild. None of it was illegal, it just was clearly not the intended purpose of the tax laws. One example I clearly remember was sticking five cattle on each of the properties they purchased, and all taxes just disappeared (went from thousands of dollars to just... dollars) due to agricultural exemptions. All of the cattle and their care suddenly became expenses, because the labor they hired to care for them was somehow completely deductible or expensable or however the law looked at it, which allowed them to shuffle money from another business to make it look negative....

and so on and so forth. I think they had more than four businesses that were legally separate (and incorporated, with the board being family members [and those family members are part of a trust that let even more shenanigans happen]) but supported the way money was shuffled. This was for a family that, at most, made ~ $500,000. Super high, above that 1% mark, but not even close to the insanity that the truly wealthy can pull off. Anything business related opens up an exponential number of ways to move money, even while using it, compared to the options a casual income-only tax-payer has.

As much as we can point at 'Trump, dumb' and tell ourselves that the rich are stupid but lucky, the majority are not at his level. They hire (multiple) people making six figures to manage their money because that investment pays off.