Master your credit score.
It determines the interest rates you'll get on loans and credit cards, and a good one—above 720—will save you money throughout your life. Visit myfico.com to get your score, understand how it's calculated, and learn how to improve it.

Enroll in your company 401(k) plan.
Most companies match your contribution; by not enrolling, you're virtually throwing away free money. The secret to investing is giving your money time to grow. If you delay saving for 10 years, you'll be hard-pressed to make up for lost time. If you're self-employed, park a Roth IRA or a SEP-IRA at a discount brokerage such as Muriel Siebert or a low-cost fund company like Vanguard or Fidelity.

Pay off credit card debt.
To calculate the shortest and most effective route to becoming debt-free, visit bankrate.com's Credit Cards section.