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The Nicklaus mouse swing is different from any other mouse swing. First of all, you can move the mouse in any direction you wish without worrying about perfectly retracing the path of the backswing on the downstroke.

The intention of the game developers is that you move the mouse in one direction for backswing (power), taking care to stop at or near the top when the swing meter's flow indicator passes by the "perfect power mark." You are then supposed to move the mouse in the opposite direction, clicking it when the flow indicator has dropped
back down to the "perfect direction mark." The catch is that the game removes some of the power you initially created for each extra millisecond you take trying to hit that perfect direction mark on the downstroke.

The cheating solution? Well, for starters, completely ignore that top power mark. Take the backswing back as far as the meter will go, right to the end of the "overswing" territory. This will give you at least one more precious second on the
way down to try to hit the direction mark perfectly. Second, move the mouse really quickly on the way down until you get relatively close to the direction mark, slow it at the last moment, fine-tune it to the mark, then let go of the button. If all goes as planned, you'll have had enough time to click exactly on the direction mark while incurring only enough
penalty time to affect the amount of overswing--your swing power will still be right up there at ideal speed or, with any luck, will be even harder. You can regularly nail arrow-straight drives of 270-plus yards using this method.

Go into the golfer edit screen and select a Fast, but not Very Fast (it's just too quick), meter speed. This will allow you to bestow more skill points to your golfer, while the extra meter speed should be of little concern if you follow the first tip above.

In Nicklaus 6, the orientation of golfer to ball at the moment of impact is crucial. If that ball sits lower than your feet, the slices can be absolutely horrific. Adjust your stance and approach accordingly.

When putting, use the aiming arrow to increase the potential power of your attempt. The game doesn't give you enough oomph by default.