Keep your statements. Be realistic when making your budget. Keep track of your income and expenses, and all of your banking transactions. Balance your statements. Use credit responsibly.
Credit is expensive.
If you don't already have the money in the bank, you can't afford it. Don't carry large amounts of cash. When receiving a sales call, be careful, ask questions, get their information in writing before making a purchase. It's okay to politely say no and hang up. Never give a credit card number, or any bank or ID information to someone who calls you.