Table tennis is very similar to a mind game in a number of aspects. Put pressure on your opponent and try to force a mistake or error without being aggressive. Your aim is to defend, not to attack. This can be best accomplished by playing for control and ensuring your return lands in the allowed area of the table.
For a shallow ball, the best way to play defense is to use a number of different defensive shots such as lobs, chops, blocks and even pushes. This will keep your opponent guessing.
Remember the age old cliche - offense is the best defense. This holds true for table tennis. Even while you are playing defensively, letting go of opportunities where you can attack your opponent is not a good idea because. Be sure to take full advantage of attacking opportunities that come by during the game.
One of the best ways to play defense is to impart as much spin on the tennis ball as possible. To accomplish this, you will be required to strike the ball with the racket at a certain angle. It does not matter which way you are spinning the ball as long as the amount of spin you get is enough to confuse your opponent.
Block everything else out of your mind and stay focused on the task at hand. Try not to lose your concentration even if your opponent is powering forehand drives down the line.
In sports, there is nothing more fruitful than extensive hours of meaningful practice. If you want to become a professional at playing table tennis, consider hiring a coach or joining practice classes at a coaching academy. Try to work around your schedule so that you can spare enough practice hours and you will eventually get better at playing defense. Remember, everybody starts from defense in table tennis.