Dump Your Debts
These days, being in debt is almost considered normal. The average UK adult has non-mortgage debts of several thousand pounds, and pays interest rates well in excess of 10% on what they owe. While the miracle of compound returns can be a fantastic thing when you're saving, it works in reverse when you're borrowing, which explains why debts often spiral out of control.
Credit cards are a major culprit here. While it's useful for borrowing money, if your card has a high interest rate and you can't afford to pay off much each month, then the credit card company is getting the benefit of compound returns - and who wants that?