Invest in index funds with the lowest fees you can find.  Seriously.  The biggest thing that will eat up your investment or retirement income is fees.  Vanguard Total Stock Market Index Fund Admiral Shares (VTSAX) has fees that are only around 0.05% per year (very good!).  Most mutual funds have fees in the 1-2% range (very bad!).  Trust me.  Your future self with thank you.