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.