Picking a mutual fund from among the thousands offered is not easy. The following is just a rough guide, with some common pitfalls.

1. Check with your tax advisor prior to investing in a tax-exempt or tax-managed fund.

2. Match the term of the investment to the time you expect to keep it invested. Money you may need right away (for example, if your car breaks down) should be in a money market account. Money you will not need until you retire in decades (or for a newborn's college education) should be in longer-term investments, such as stock or bond funds. Putting money you will need soon in stocks risks having to sell them when the market is low and missing out on the rebound.

3. Expenses matter over the long term, and of course, cheaper is usually better. You can find the expense ratio in the prospectus. Expense ratios are critical in index funds, which seek to match the market. Actively managed funds need to pay the manager, so they usually have a higher expense ratio.

4. Sector funds often make the "best fund" lists you see every year. The problem is that it is usually a different sector each year (internet funds, anyone?). Also, some sectors are vulnerable to industry-wide events (airlines do come to mind). Avoid making these a large part of your portfolio.

5. Closed-end funds often sell at a discount to the value of their holdings. You can sometimes get extra return by buying these in the market. Hedge fund managers love this trick. This also implies that buying them at the original issue is usually a bad idea, since the price will often drop immediately.

6. Mutual funds often make taxable distributions near the end of the year. If you plan to invest money in the fund in a taxable account, check the fund company's website to see when they plan to pay the dividend; you may prefer to wait until afterwards if it is coming up soon.

7. Research. Read the prospectus, or as much of it as you can stand. It should tell you what these strangers can do with your money, among other vital topics. Check the return and risk of a fund against its peers with similar investment objectives, and against the index most closely associated with it. Be sure to pay attention to performance over both the long-term and the short-term. A fund that gained 53% over a 1-yr. period (which is impressive), but only 11% over a 5-yr. period should raise some suspicion, as that would imply that the returns on four out of those five years were actually very low (if not straight losses) as 11% compounded over 5 years is only 68%.

8. Diversification can reduce risk. Most people should own some stocks, some bonds, and some cash. Some of the stocks, at least, should be foreign. You might not get as much diversification as you think if all your funds are with the same management company, since there is often a common source of research and recommendations. The same is true if you have multiple funds with the same profile or investing strategy; these will rise and fall together. Too many funds, on the other hand, will give you about the same effect as an index fund, except your expenses will be higher. Buying individual stocks exposes you to company-specific risks, and if you buy a large number of stocks the commissions may cost more than a fund will.

9. The compounding effect is your best friend. A little money invested for a long time equals a lot of money later.