When to slice - you should aim to slice the fruit once it reaches the top of its journey. This is when it is either moving at its slowest or completely staionery, making hitting it easier.
Aiming - the best tactic for aiming at the fruit is to slice diagonally. This gives you better coverage up-to-down and so increases your likelihood of scoring a hit.
Finger connection - when playing Fruit Ninja, it is important to ensure the game recognizes that your finger is connected to the screen and that it picks it up properly. To do this, you should keep it moving on the screen whenever there is no fruit. This will also allow you to react quickly to any fast fruit. Try to keep your finger touching the screen as much as possible.
How to get High Scores - A trait required in order to achieve a high score in Fruit Ninja is patience. Even if you have a brilliant round, the random placement of the bonus items may well mean you have, through no fault of your own, been given a harder time trying to get a high score.