By Maggie Puniewska Set yourself up for a wealthier new year by following these time-sensitive tips from financial experts. Fully fund your retirement account. Put as much as you can into a traditional 401(k) or IRA before the end of the year. A higher contribution can lower your taxable income, so you could pay less in taxes in April, says certified financial planner Misty Lynch, head of planning at John Hancock in Boston.