KEEP REALLY GOOD RECORDS

Keep really good records of all your expenditures. This means "EVERYTHING"!!  Whether you think the expense applies to your business or not. Who knows? When you sit down with me, I may find a legal way to claim that expense as a write-off. BUT -- without those receipts, even the courts can't help you when the IRS denies your deductions.

Incidentally, a credit card statement is not enough. You need to keep the actual receipt that shows what was purchased.