Carry An Envelope Everywhere
Bring a small envelope with your everywhere you go to keep your business cards and receipts stored safely. You want to do this so you can keep a paper trail. You won't know when you need to deal with twice being charged for something on your credit card.
Most people toss receipts immediately, these days. Don't be one of those people! Keep your receipts.
Set something up that will automatically send money from a portion of your cash into a savings account every month. You'll increase your savings over time and also have money for events like vacations or weddings.
If you've got debt, remember that it could expire. Talk with an expert and determine if your debt will expire after some time. If it's true, don't bother paying a nickel to the collections agency.