Instructions
Adjust your lane position. Like in real bowling, if you stand directly in front of the head pin and roll a ball straight at it you are likely to end up with a tough split instead of a strike. Use the directional pad to move your Mii character to the left of the head pin if you left-handed and to the right of the head pin if you are a righty.
Hold the "B" button on the bottom of the Wii remote while swinging your arm backward.
Tilt the Wii remote slightly to the left (if you are right-handed) or the the right (if you are left-handed) to put some hook on your shot as you bring your arm forward.
Release the "B" button as your arm comes in front of your body in the same manner you would release the holes of the bowling ball at the end of your swing on the real lanes. If the shot is done correctly your ball will hook into the pocket between the head pin and the second row of pins for the perfect strike.