Should you be a beginner in table tennis, just ensure that you get to a point where you can rally a bit, return serves, and occasionally be protected from smashes first. This will take a few hours, over a few days to get your eye in. The simple trick here is to just keep playing. Once that's attained, follow these steps - pick one to start - get them right and improve your repertoire.
SERVE A VARIETY
Don't be predictable with your serves. Mix it up a bit - make a couple short, a few deep, mid-range, and vary the spin and speed. The trick here is to gradually open and perfect the varied serves. So, take it a step at a time.
Surprise your opponent. Hit one back, make it on the edge to keep your rivals moving early rather than settling them down with a rally. Smash one right after a serve, or land one on the edge to ensure there is enough movement at the other end of the table.
FOCUS ON RETURN
Wear 'em down. Just focus on returning the ball to the other end. This will eventually tire the other person, and force an error. This requires immense concentration, but once achieved, it will build your game all round. A sudden attack after a prolong period of rallying can catch your opponent off guard.
VARY RETURNS TOO
One way of attacking is to keep the other person guessing your strategy. As stated in the serve section, Mix it up a bit - make a couple short, a few deep, mid-range, and vary the spin and speed.
EYE THE PADDLE
The secret to any sport involving a ball is to pick up body cues from rivals. The angle of the arm, the racket, how high the ball is tossed, and anticipating movements. This usually settles in the subconscious as you gain enough experience. Don't focus on the ball too much; as your mind will calculate its trajectory anyway.
KEEP KIT IN ORDER
Make sure you are comfortable in your attire, no loose sleeves to distract you, comfortable socks, the right paddle/blade. Keep these avenues shut and it will allow you to focus on the game.
You'll easily figure out whether your forehand or backhand is your forte. Whatever that may be, make sure you have the other sorted too. Keep practicing your weak hand and get to a level where you don't get handicapped.