A 77-year-old Chinese woman named Jin Guangying had lived with a headache for 64 years. After finally getting examined, she learned its source: There was a bullet in her head.

Back in 1943, she'd been shot by a Japanese patrol. She'd lost consciousness at the time, waking up with a bandage wrapped around her head and no clue that she'd been hit, much less that the bullet remained in her skull. Amazing, eh?

Call me a little demented, but this made me think of finances.

What's your bullet?
Most of us have undiagnosed problems with our money management style -- problems that can keep us from performing as well as we otherwise might. See if any of these ailments plague you:

  • Impatience. Look at how you trade stocks (or funds) within a few months or a year. Do you buy promising investments and aim to hang on for a long while, while they reach their potential and continue to achieve new heights? Or do you get tired of waiting for a pop in their price, selling them to buy something else that looks promising?

  • Superficiality. I've done this too many times. I'll read some great things about a company, and look into it a little before buying. I'll have seen some great numbers, such as a strong return on equity. But if I haven't looked at the big picture, I can end up blindsided. Perhaps those relatively hefty profit margins are currently falling. Perhaps inventory has been piling up. Perhaps the company owes its high return on equity to a pile of expensive debt. Heck, maybe there's a competitor around the corner with a more exciting alternative product!

  • Overconfidence. True, many of us would do better managing our own money than letting some salesperson at a brokerage firm direct us in and out (and in and out and in and out) of various holdings. We'd certainly save a bundle in commission fees. But that doesn't necessarily mean we're better than the pros at studying and selecting the best stocks and funds. Do you really know your way around financial statements? Do you spend many hours each day reading up on and studying lots of companies? If not, you're probably at a disadvantage, especially compared with the best fund managers out there.

What to do
So what should you do? First, examine your own head to see what financial "bullets" may be lodged there. Then remove them.

If you find that you're impatient, apply more inactivity to your portfolio. (Within reason, of course. If a stock starts plunging, learn why, and consider selling if the long-term prognosis is bad.) If you're not good about digging deep into a prospective investment, well ... that's a reason to consider tapping the services of professionals. And if you're overconfident, dial that exuberance down a bit. We tend to remember our successes more, but our failures can teach us some valuable lessons.

I'm dealing with my own shortcomings by investing more and more in mutual funds. I still venture out into individual stocks I've selected on my own, but I'm entrusting some big chunks of my money to fund managers with sound principles, great track records, and promising futures.

For example, T. Rowe Price Media & Telecom (PRMTX) has racked up average annual gains of nearly 28% over the past five years and 19% over the past 10. Its top holdings recently included Rogers Communications (NYSE:RCI), Google (NASDAQ:GOOG), America Movil (NYSE:AMX), and International Game Technology (NYSE:IGT). Dodge & Cox Stock (DODGX) has averaged close to 17% over the past three years and nearly 14% over the past decade. Its top holdings include Hewlett-Packard (NYSE:HPQ), Sony (NYSE:SNE), and Sprint Nextel (NYSE:S).

If you'd like to find some great funds tailor-made for your own portfolio, sign up for a free trial of our Motley Fool Champion Funds newsletter. Its picks are beating the market by some 14 percentage points, and last time I checked, none of them were underwater. A free trial will give you full access to all past issues, so you can read about each recommendation in detail.

Longtime Fool contributor Selena Maranjian owns shares of T. Rowe Price Media & Telecom and Dodge & Cox Stock. For more about Selena, viewher bio and her profile. The Motley Fool is Fools writing for Fools.