There's nothing like an agitated market to make traders focus on getting the most out of their trades.

As Internet stocks popped over the past few weeks, some online traders have been frustrated with the executions on their orders. We have looked at what the key

elements

are in determining whether your online broker generally delivers good executions -- a fast trading system, direct access to an electronic communication network, or ECN, and a refusal to sell order flow. But the volatility in some Internet stocks has reinforced that there are a few other things online investors should keep an eye on to make sure they're buying and selling is done as economically as possible.

On a calm day, the Internet makes trading seem so easy. You place a market order and you get an electronic order confirmation a minute later showing it was executed close to the price quoted when you entered the order. No sweat. But if you're trying to buy or sell a volatile stock, that scenario can play out quite differently, with slower fills or order confirmations and eye-popping execution prices. And when you're trading online, nothing stands between you and placing a sub-par order except your own expertise.

"This is a very exciting market and people who wish to trade or invest in it should make sure they understand the rules of the road," says John Chapel, president of

Waterhouse Securities

, a unit of

Toronto Dominion Bank

(

(TD) - Get Report

TD: NYSE). While most factors influencing executions are beyond the trader's control, brokers have some advice about how to avoid common pitfalls.

Be Careful Around the Open:

"When you think about the open, think of it as a bottleneck," says

Charles Schwab

(

(SCH)

SCH: NYSE) spokesman Tom Taggart. Trades pile up before the open and then when the bell goes off market makers get to work on the stack of orders.

The problem is a trader typically doesn't know how many orders are out there or if they're buys or sells. So it's tough to tell which direction the stock might head in the minutes after the open or how long executions might take. Stocks that are trading for the first time or that have been volatile can have especially tumultuous opening minutes.

"Once the open as occurred, you have a better and clearer picture of what's transpiring," says Chapel.

Perils of Trade Cancellation:

The problems involved with canceling trades came into the spotlight several weeks ago when Schwab cautioned customers about the practice and pushed traders to brokers to trade certain Internet stocks.

Traders accustomed to order confirmations popping up within seconds can be quick to cancel if minutes go by without a confirmation. The problem is that the trade may have been executed even if the confirmation is tardy. If the trader cancels and then sends in another order for the same stock, unwanted duplicate orders can pile up.

Trade cancellation should be done judiciously. Traders should consider the price they're willing to pay before they enter an order and use a type of order that takes that into account, instead of canceling when the stock goes out of a desirable range. Some brokers offer cancel/replace orders so if an order hasn't been executed, it's canceled and automatically replaced with the new order. If it has been executed, the replacement order is canceled.

Choose Your Orders Wisely:

One stock is flying, another is plunging on heavy volume, while yet another is trading placidly. Just as you don't dress the same way for every occasion, don't use the same type of order for every trading situation.

Traders have to ask themselves whether they're interested in the stock at practically any cost or because it's a good value a particular price, says Lisa Nash, an

E*Trade

(

(EGRP)

EGRP: Nasdaq) spokeswoman. That choice has to be matched up against what's going on in the market for the stock at the time. "Embedded in every trade is a compromise," says Chapel at Waterhouse.

Market orders, orders to buy or sell at the best available price, take precedence over all other orders. They'll get filled eventually and, at some brokers, they're cheaper than other types of orders. If you really want the stock, are looking to make it a longterm investment or if the stock trades at a pretty even keel, market orders are a good bet.

But with a market order, you run the risk of getting filled at a price far from where the stock was trading when you place the order. Especially if a stock is jumping around erratically as some Net stocks have been, market orders can produce nasty surprises. Indeed, some brokers have limited market orders in early trading of certain IPOs.

Traders know they have a whole rash of orders available to them to limit the price they're willing to pay for a stock or the length of time they're willing to wait for a fill. They have their tradeoffs, too.

The point, brokers say, is to examine all the options. Common order include limit (to buy or sell at a specific price or better), stop (to buy or sell at the market after the stock has traded at a particular price), "all or none" (to prevent partial fills) and "good through" (to buy or sell at a particular price for a particular length of time). But acceptable orders vary between brokers. Customer service representatives or education sections on broker Web sites can help traders figure out what's available to them.