Once online, many investors tend to concentrate on stocks, specifically large-cap domestic stocks. While these stocks should make up part of your portfolio, they shouldn’t be ALL of it! Take into account your time horizon and risk tolerance to develop a well-balanced portfolio of stocks, bonds, and cash.

Most investors are in mutual funds for a good reason. They don’t have the expertise to make their own investments calls on individual stocks. They also are too preoccupied by work, family and other concerns to spend every minute watching the market. So keep your mutual funds; it probably is an unwise move for you to cash out your long-term fund holdings so that you can start playing the market in individual stocks!

Even if online brokerage costs are lower than those of full-service brokers, they can still add up, particularly if you do a lot of buying and selling. Online brokerages firms also impose a number of other fees and charges that you should study closely. The federal capital gains tax is also something with which you must reckon. Before you start buying and selling stocks or mutual funds online on a large scale, you should give careful thought to what the tax bite would be as a result of such trading.

If you are going to do your own investing online, you need to learn how to use the tools available to avoid potentially steep losses and to buy or sell a stock at attractive prices. Here are three orders that you should use to your advantage:

A MARKET order is an instruction to buy or sell a specified amount of a stock (or other security) at the current market price. The advantage of a market order is you are almost always guaranteed your order will be executed — as long as there are willing buyers and sellers. Depending on your firm’s commission structure, a market order may also be less expensive than a limit order.

A LIMIT order allows you to avoid buying or selling a stock at a price higher or lower than what you specify. A limit order is an order to buy or sell a security at a specific price. A buy limit order can only be executed at the limit price or lower, and a sell limit order can only be executed at the limit price or higher. By contrast, a market order only guarantees you the best available price — not the limit order’s specified price.

A STOP-LOSS order sets a sell price for a broker. When the price of the stock drops below this level, it automatically is sold. Also: Take the time to learn about stop orders, day orders and good-till-cancelled orders

Limit orders are often used to guarantee that an investor will not pay over a certain dollar level for a stock. If no limit is placed, the trade is considered to be a market order. Placing a market order means you won’t necessarily get the price you see when you buy or sell online. Here’s how that works: an investor places an order for a fast-moving stock at $10 share price, but the order does not reach the market until the stock’s price is at $15 a share.

Trading online is not foolproof. There will be times when you can’t access your account. You could be away from your computer when the market makes a major move. Your Internet connection could be down. The online brokerage firm’s server could crash due to heavy trading, unexpected software glitches or a natural calamity. Know about the firm’s alternative trading options. This could include automated telephone trading or calling a broker.

If you are going to buy and sell individual stocks online, it is your duty to keep as well informed as possible about what is going on with the company in question. Don’t just settle for the hype about hot stocks! Go to the company’s Web site and download its prospectus. Check out the company’s publicly available filings through the U.S. Securities and Exchange Commission’s EDGAR system. Take advantage of free services that allow you to get automatic e-mail messages whenever there is news about your stock.