Falling a little behind in a Tournament? Here are a few tips to help you seize the day.
First, the easiest way is to make your character a Star by beating them in a Character Match. The Star will raise the character's drive by at least 30 yards, in addition to all of the other shots the character makes being able to go longer. If you haven't played CM before, notice the Letter on Koopa's icon? Beat him, and he becomes a Star. You then get a Letter from Peach. Eventually, though it may take time, particularly if you're using a strong character like Bowser or Mario, the next Letter will be from the character you want to use. Upon upgraing that character to Star status, start the tournament fresh, being careful to hit the R Button when selecting your character. You should have less trouble now.
Also, remember to use Power Shots. That's what sets you apart from the AI: Nintendo and Camelot conviently forgot to give the computer-contolled characters the ability to use Power Shots. Use this to your advantage!
Finally, take a moment to collect yourself before taking a shot. Remember that the 1W is not the ultimate weapon... It has some drawbacks, namely a very low arc and a small Time Range (the "safe zone").