There is only one way: keep scrupulous records of things that decrease your profits and therefore your tax burden.  That's not so difficult when you're in business.  Keep a mileage log, keep receipts from business-related meals, and write off your home office.  The tough part is not coming up with zany ideas that end up red flags for the IRS.  Common examples is people trying to write off their cell phone usage, or trying to write off their clothing as a uniform, or their car as a company car.  In a sense, if you're not a crook, you'll never be able to predict the type of paper trail necessary to prove you're not a crook.  Since there are 300M people in the US, every little idea you come up with already has special rules already created from millions of pages of precedent.  All of the above especially raises flags if you're getting Earned Income Credit while having a Schedule C.  So while you can easily minimize your taxes, you do have to pay a pro to do your taxes once you start trying anything.