Hooking in golf is caused by coming too far under of the swing path. Usually your club face is at the target or closed to the target when you come across the ball. It usually stems from a lack of body rotation. Hooking problems are also derived from a strong grip that keeps the club face closed at impact, and causes the "Dumped Under" movement.
The solution to hooking is not a gimmicky golf tip or drill. Those will only provide a temporary solution. A permanent solution comes from an understanding of ball flight laws and clubface control. It is imperative to note that the golf ball always curves away from the path direction. Swing left, the ball will go right. Swing right, the ball will go left.
For a lasting solution to fix a hook, use this drill to work on emulating a proper body motion that will promote a swing path that is more left of the target. Starting by incorporating a feeling of less turn and more fold at start of your swing. This will help promote an Out to In path at impact. When this drill is executed properly the unwanted hook will be forever gone and a permanent fix will be ingrained.