2. Discipline yourself to build up your emergency fund to six months' worth of living expenses. You should also pay off any high-interest debt (at least 10 percent APR) you're carrying. This is especially important in the likely event that the interest rate you're paying on such debt exceeds the interest rate you could expect to earn with your investments. See how to decide whether to invest or pay off debt for more information.

• If the interest payment on your debt is higher than what you'd be making with an investment, it's probably not wise to invest at first. In this case, try to pay off all your debt before investing your surplus; that way investing will actually make you money instead of merely underwriting your monthly debt payment.