For many individuals, the 2013 federal tax rates on long-term capital gains are the same as last year: either 0% or 15%. However, the maximum rate for higher-income individuals is now 20% (up from 15% last year). This change only affects taxpayers with taxable income above $400,000 for singles, $450,000 for married joint-filing couples, $425,000 for heads of households, and $225,000 for married individuals filing separately. Higher-income individuals can also get hit by the new 3.8% NIIT on net investment income, which can result in a maximum 23.8% federal income tax rate on 2013 long-term gains.

As you evaluate investments held in your taxable brokerage firm accounts, consider the tax impact of selling appreciated securities (currently worth more than you paid for them). For most taxpayers, the federal tax rate on long-term capital gains is still much lower than the rate on short-term gains. Therefore, it often makes sense to hold appreciated securities for at least a year and a day before selling to qualify for the lower long-term gain tax rate.

Biting the bullet and selling some loser securities (currently worth less than you paid for them) before year-end can also be a tax-smart idea. The resulting capital losses will offset capital gains from other sales this year, including high-taxed short-term gains from securities owned for one year or less. For 2013, the maximum rate on short-term gains is 39.6%, and the 3.8% NIIT may also apply, which can result in an effective rate of up to 43.4%. However, you don't need to worry about paying a high rate on short-term gains that can be sheltered with capital losses (you will pay 0% on gains that can be sheltered).

If capital losses for this year exceed capital gains, you will have a net capital loss for 2013. You can use that net capital loss to shelter up to $3,000 of this year's high-taxed ordinary income ($1,500 if you're married and file separately). Any excess net capital loss is carried forward to next year.

Selling enough loser securities to create a bigger net capital loss that exceeds what you can use this year might also make sense. You can carry forward the excess capital loss to 2014 and beyond and use it to shelter both short-term gains and long-term gains recognized in those years. Note that the wash sale rules can limit the deduction for securities losses.