1. Establish your game. For example, if you have a strong third-ball attack, such as short backspin serves followed by a loop, then do that early on. That way you’ll get used to your opponent’s returns. For example, against that backspin serve, does he predictably push long and let you loop? Or does he flip it or push short? If necessary, change your serving pattern to get better balls to attack, perhaps by serving lower, with more spin, more variation, different placement, and/or different depth. Do the same with the rest of your game. For example, if you do a lot of backhand counter-hitting, then establish that early so you’re comfortable against this opponent.
2. Adjust to opponent's game. There are two players at the table, and so you also have to adjust to the opponent. If you want your opponent to push your serve back long so you can attack, but he stubbornly attacks your serve or pushes it short, then you have to make adjustments. For example, you might fake backspin and serve no-spin, and watch him pop the ball up slightly. Be willing to change your serving game. The same is true of the rest of your opponent’s game – everyone has something you have to adjust to. The more you play, the more you learn about how to make those adjustments. 
3. Find a way to win. That means finding the best tactical matchup of your game versus the opponent's. This means taking best of 1 and 2 above and finding a few simple tactics that win, and then thump your opponent with them.

1. Tie your shoes tight so there’s less give when you move.
2. Grippy shoes on non-grippy floors.
3. Great ready stances give great starts. This means you and your racket’s tip are facing where the opponent will contact the ball, knees slightly bent, leaning forward slightly from the waist, weight mostly on the front inside part of the foot, feet pointed slightly outward, ready to move in either direction.
4. Have as wide a stance as you are comfortable with. Top players, who train constantly and are in peak condition, have very wide stances. The better shape your legs are in, the wider you can and should make your stance, which gives more stability, a lower center of gravity, a quicker start, and more power.
5. Fitness means faster feet. Lose those extra pounds!
6. Balance. If you are even slightly off balance, it dramatically slows your start.
7. If you focus on positioning so that you’re are always in position, you don’t need to move as much, and so you can get to each ball.
8. Mentally alert, ready to reflexively react to your opponent’s shot.
9. Mind clear so you don’t try to consciously guide your movement. Let your trained subconscious take over for both footwork and strokes.
10. If you have the will to move, you’ll move at will.

Let’s face it; they’re probably faster than you. They might have a coach working with them regularly and in their corner in a match. They often have near perfect strokes, thanks to that coach. They strive in super-fast rallies, the type where your game starts to crumble.

So . . . what to do?

The real problem most players have with playing kids is that they don’t play them regularly and aren’t used to playing them. It’s like any other style that you don’t play regularly. If you don’t play long pips somewhat regularly, you will likely struggle against them in a match. If you don’t player strong loopers somewhat regularly, you will likely struggle against them in a match. If you don’t play kids somewhat regularly, you will struggle against them.

If you play them regularly, then you will soon learn and become comfortable playing them. You have many advantages, number one being experience. But guess what? If you don’t play kids regularly, then you aren’t experienced against them, and you lose that advantage. Ironically, they may have more experience playing adults then you have playing against kids!

So, what are your advantages over kids? They do not all play the same and there’s no one thing that will work for certain, but in general:

1. They have shorter reach, and so cannot cover the corners as well.
2. They have trouble against shorter balls, especially short to the forehand.
3. They do not react to changes in spin very well.
4. They have trouble attacking heavy backspin.
5. They are not good in slower rallies, such as against backspin or soft, deep topspins.
6. They do not have as much power to end the point against high balls, especially lobs.
7. They do not vary their serves very well.
8. They have trouble if you vary your serve a lot.  
9. They are not experienced in adjusting their tactics to you.
10. They play predictably.
11. They are more emotional and often play poorly under pressure, or when they can’t play their normal bang-bang games.

That’s eleven things to get you started, enough to win the first game, 11-0! But the key is to be aware of these potential weaknesses, and then play kids until you get used to them. Then you will lose your fear of those little tykes!

This is one of those tips where the title, by itself, should give you a lot to think about.

If you want to improve at table tennis (or most other endeavors), you need to constantly learn. I’ve been playing almost 50 years, and just last week I think I finally figured out how best to block spinny loops with my backhand. That doesn’t mean I was really bad at blocking spinny loops before with my backhand or that I didn’t know how to; it means I wasn’t as good as I could be, and now it’s better. It also doesn’t mean I was dumb because I didn’t figure this out for 50 years; it means I was smart enough to constantly strive to get better. If you play 1,000 years, you should still find things to improve on.

The same is true of all players at all levels. Some players think of themselves as “smart” players, and so they are confident that they’ve figured out, for example, how to play a particular player. If so, then you have just stagnated yourself. Instead of thinking you’ve figured that player out, think about how he could adjust to your game or tactics, and prepare for that – or for a future, similar player who might make that adjustment. Or whatever it is you successfully do against them, strive to do it better, both because that player may improve, or because you may need those same tactics at a higher level against a stronger player.

Is there a shot in the game that you think you’ve mastered? That would be a pretty dumb thing to believe, wouldn’t it? Long ago, after years of regular practice, I “mastered” the fast down-the-line serve to the point that someone once wrote in a published article that I did it better than anyone in the US. I could fake the serve crosscourt so that receivers would move that way, and at the last second I’d flick the serve down the line for an ace or service winner. I was pretty proud until I saw Jan-Ove Waldner do it with even more deception, speed, spin, and even closer to the line, and I realized how much better I could make the serve – and I tried to do so.

It's true that when you first started out playing, you didn’t know much about the sport. You weren’t dumb; you simply were at the start of a long learning curve. If you knew you had a lot to learn, and strove to learn, you weren’t dumb. You were smart!

The only way you were dumb before – or now – is if you stop learning. Now that would be really dumb.

Players with great reflexes don’t have great reflexes.

There, I’ve said it, and you probably think I’m crazy. But they don’t. What they have is early reaction. What does that mean?

If you smash or loop kill against a top player, it’s often amazing how they seem to react to it, thereby allowing them to return them, over and over. And much of that is high-level skill, developed from years or decades of practice.

But here’s the secret – there’s a “cheat” factor. While mere mortals react to the ball coming off the opponent’s racket, the top players react well before that. And so can you.

The key is to make it a habit to watch opponents and learning the clues of where they are going. For example, on most forehand shots it’s the shoulders. While advanced players can sometimes change directions at the last second, the large majority of players are focused on just getting their attack on the table. They may change directions, but they commit to the direction early in their swing. The huge majority of the time you can see where their shot is going by watching their shoulders right as they start their forward swing, well before contact. And THAT is when the top players react. And with that head start – plus a good ready position, proper footwork, and athleticism – allows them to have such seemingly incredible reflexes.

This is reminiscent of the 1995 movie “The Quick and the Dead,” where the bad guy, played by Gene Hackman, was not only a great gunfighter, but in the arranged shootouts in the street, where both shot when the minute hand of the clock reached 12, he also had a “cheat” – he knew there was a tiny click just before it reached 12, and so drew before his opponents. So, be like Hackman – except in table tennis, it’s not cheating, it’s just smart! (The movie also starred Russell Crowe, Sharon Stone, Gary Sinise, Lance Henriksen, and Leonardo DiCaprio. Wow.)