Think about increasing your charitable contributions. Donating assets that have appreciated over time can help pre-retirees avoid capital-gains taxes while also helping a worthy cause. "We hear very consistently that it's an important element of their financial planning," said Fidelity Investments' Kathleen Murphy, who oversees $1.7 trillion in assets as president of the firm's personal investing business.
Read MoreThe pros and cons of donor-advised funds
It's also possible to increase the tax benefits today and delay the actual gift until a later time by making a charitable contribution to what's known as a donor-advised fund. Begin by projecting how much you'd like to give over the course of 10 years or longer, then transfer that amount into the fund, which will allow you to get an immediate tax deduction on the donation today, when it's most advantageous (since you're likely in a higher tax bracket).
From there, you can make decisions on how, when and where you want your donations to be distributed.