The new Roth IRAs are selling like hotcakes - more than a year ahead of the typical predeadline rush.

At Charles Schwab Corp., total sales of individual retirement accounts are up 200 percent so far this year, and half of the IRA contributions are going into Roth IRAs. Fidelity Investments says IRA sales are up 30 percent year-to-date, with nearly two-thirds of money going into Roths.That's surprising because in previous years, investors have been so blase about IRAs that they generally haven't contributed to them until just before the deadline.

Investors actually have another entire year, until April 15, 1999, to contribute to a Roth, which takes effect in tax-year 1998. (They have until this April 15 to make 1997 contributions to a traditional IRA.) Some people are contributing to both at the same time, but for the different tax years.

You can set up an IRA at a bank, brokerage firm or mutual-fund company. Many people prefer to keep their IRAs in funds, rather than individual stocks, because funds offer diversification and professional management yet they tend to be tax "inefficient": They usually make big capital-gains payments to investors once a year. With stocks, you pay taxes on dividends, but you can defer paying taxes on capital gains until you sell the shares.

How should you go about picking a fund for your IRA or Roth IRA? The answer depends largely on your tolerance for risk and the makeup of your investment portfolio. Because most people funding IRAs don't withdraw the money for a decade or more, investment advisers generally suggest mainly aggressive stock funds that stand the best chance of producing inflation-beating gains. But that advice doesn't make sense for everyone, particularly not people who may need to tap their IRA accounts within a few years.

What follows is a thumbnail description of some IRA investing strategies suggested by some fee-only investment advisers:

Tax bombs with good returns

For those who need to boost their stock-fund holdings, one way to take advantage of your IRA or Roth IRA is to use it to shelter your tax bombs - funds that tend to make big taxable capital-gains distributions. "Unquestionably, the best investments" for the tax-deferred accounts are funds that "can be expected to perform well, but that aren't particularly `tax efficient,"' says Daniel Roe, a fee-only investment adviser in Columbus, Ohio.

For example, Roe figures Heartland Mid-Cap Value Fund, Brandywine Fund and Skyline Special Equities are promising, but he would hold them only in tax-deferred accounts. Each fund's manager, he says, tends to trade stocks frequently, and rapid-fire trading usually brings about the unpleasant side effect of big capital-gains distributions. IRAs are "the perfect way to eliminate the tax liability" of an otherwise excellent fund, he says.

Funds with low expenses

No matter whether a stock fund or bond fund is better for you, you can only contribute as much as $2,000 a year to an IRA or Roth IRA, so it makes sense to look for ways to "get the most bang for your buck," says Linda Gadkowski, an investment adviser in Centerville, Mass.

The best way to do this is to emphasize funds with low ongoing expenses, says Gadkowski. She suggests focusing on funds sponsored by Vanguard Group, Malvern, Pa., such as Vanguard Prime-cap (for aggressive investors), and Vanguard Wellington or Vanguard Wellesley (for the more conservative set).

Funds paying lots of taxable interest and dividends

If your taxable accounts are overloaded with stocks - and you need to tone down the risk level of your portfolio - consider using your IRA or Roth IRA as a home for funds investing in bonds, stocks paying high dividends, or real-estate investment trusts, or REITs. Held in taxable accounts, these funds will pay income that is taxed at rates as high as 39.6 percent (compared with the 20 percent many investors pay on capital gains).