From Rich Dad, Poor Dad. 3 Major Things:
- Business Expenses
- Real Estate
With rental real estate, in addition to mortgage interest, you also deduct property taxes, and must claim depreciation (cost of house / 27.5 years)
Business Expenses. For example, buy a yacht and put it in a charter fleet. Deduct interest on the loan, depreciation of the asset, property taxes, upkeep of the boat. Your "business" earns profit from chartering the boat, which if I recall correctly is taxed at a lower rate. You get to go sailing for free.
Then there was the concept of subdividing the businesses. If you own a restaurant, create another business to own the property, and the equipment used in the company. Then lease the equipment and rent the land to the restaurant. Now admittedly I thought this was like the Daylight Savings plan of tax avoidance, I mean now aren't you essentially having two companies paying half the taxes. I am sure there are well paid CPAs that make the math happen, perhaps using insurance plans.. Perhaps each business funds a "whole life" insurance account, and contributes vast amounts into that. Then you take a loan from your insurance account. Loans of course are not income, so not taxed.
The third way is to create your own bank. Banks are required to have reserves of 9%. Meaning if I have $100 dollars, the FDIA allows me to loan $1,111. I then charge you 20% interest, or $222/yr. Now how much can I loan?
...well you can see how profitable that is. Sure you pay taxes, but when you print your own money who cares?
Most of this is just gleamed from books, and government publications, but that was my general understanding of it. Feel free to correct the finer points.