Investing isn't just about what stocks to buy; you also have to know where to buy them. Making the most of tax-favored retirement accounts like Roth IRAs is crucial in saving the most you can for your retirement.

In the following video, Dan Caplinger, The Motley Fool's director of investment planning, takes a closer look at how to find smart stocks to buy for your Roth IRA. Dan notes that Roth IRAs give you tax-free treatment on dividends and capital gains from your investments, making it smart to look for the stocks that will provide maximum growth in your portfolio.

To give an example, Dan talks about the 3-D printing industry and how mixing established players 3D Systems (NYSE:DDD) and Stratasys (NASDAQ:SSYS) with up-and-coming players Organovo Holdings (NASDAQ:ONVO) and voxeljet (NYSE:VJET) in a Roth can give you the benefits of strong growth from whichever companies ends up winning in the space while letting you sell out of slower growers without worrying about tax consequences. In addition, Dan points out that even Apple (NASDAQ:AAPL) could make a reasonable Roth IRA choice, with deep-value appeal and sheltered dividends making an attractive combination.

Dan concludes that you don't want to have losers in a Roth, but speculative plays are sometimes worth considering if the high-growth potential they have outweighs the risk involved.