What is the best tax deduction?
There are several best tax deductions:
The first is to have your own corporation, as many expenses are both personal and business and the business aspect becomes a write off. This is the best.
The second one is a deductible retirement plan like a 401k or IRA where the money you put into it becomes a deduction as well as a earns tax deferred. You get to save and take the contribution as a a tax deduction.
If you can focus on these, it will serve you well.