Take profits near the upper channel line. If the market is strong, you can wait for the channel line to be hit. If it's weak, grab your first profit while it's still there. What if a strong swing overshoots the channel line? An experienced trader may shift his tactics and hold a little longer, perhaps until the day when the market fails to make a new high. A beginning trader is better advised to take profits after the channel line has been hit as it's important to learn to take profits in accordance with one's trading plan.
The bid–ask spread is two sides of the same coin. The spread can be viewed as trading bonuses or costs according to different parties and different strategies. On one hand, traders who do NOT wish to queue their order, instead paying the market price, pay the spreads (costs). On the other hand, traders who wish to queue and wait for execution receive the spreads (bonuses). Some day trading strategies attempt to capture the spread as additional, or even the only, profits for successful trades.
In addition to knowledge of basic trading procedures, day traders need to keep up on the latest stock market news and events that affect stocks—the Fed's interest rate plans, the economic outlook, etc. So do your homework. Make a wish list of stocks you'd like to trade and keep yourself informed about the selected companies and general markets. Scan business news and visit reliable financial websites.