1. Know the rules, or at least the more important ones.
2. Examine opponent’s racket at start of match. Don’t rub your fingers over the playing surface, which can get grease on it and anger your opponent. If he has pips, then perhaps rub your finger on one along the edge. If it’s antispin, some players rub a ball along the edge to test it.
3. Two-minute warmup. Usually players hit a minute of forehand to forehand and a minute of backhand to backhand. Players with combination rackets sometimes use their “normal” inverted side during this warmup, but that’s up to the player.
4. Hide the ball or flip a coin to see who has choice of serving first, receiving first, or choosing a side. If you choose to serve or receive, the opponent can choose the side to start on. If you choose the side to start on, the opponent can choose to serve or receive.
5. Remember that you only have one minute between games or in one time-out per match. Use it well, either talking to your coach, clearing your mind, or resting. You can also towel off every six points.  "You can also towel off every six points." 
6. A coach can talk to you during the match, but you can't stop what you are doing to listen or walk over to him except between games or in a timeout. It’s an advantage if you and your coach speak a language that your opponents do not since then he can yell tips that the opponent cannot understand. Signals sometimes help.
7. Know how to hit balls that come into your court back to their tables. Don’t just smack it at them. If they are a distance, hit with backspin so the ball floats right into their hands. New players should practice this.
8. Normally do not talk to an opponent except on match business. A common psychological ploy is for an opponent to praise your shots, thereby getting you to think about the shot and taking you out of the “zone” where your training takes over. Once a match has started, if an opponent talks to you in any way that’s not normal match business (such as, “Whose serve is it?” or “What’s the score?”), you should normally ignore him. (Perhaps smile and nod while focusing on the next point.)
9. You can only have one coach in a match, except in team competition. In team competition, anyone from your “bench” can coach during any match.
10. If there's a dispute, call for an umpire or referee. Umpires umpire matches. Referees rule on the rules but generally do not umpire unless they assign someone else as referee.
11. Win or lose, after the match shake hands, or bump fists or rackets, and fill out the scores (usually by the winner), and return the match slip to the desk.

This really could mean two things. Some players try to unsettle their opponents by staring at them between points or when about to serve. I’ve never been able to decide whether this is proper gamesmanship or poor sportsmanship. You decide.

But there’s a more important stare, and that’s the one that allows you to regain or keep focus. There are a lot of distractions in a match, both external and internal. External is all the things going on around you – spectators, the opponent, the umpire, noises, lights, the background, and so on. Internal is more important – that’s your internal emotions and thoughts. Nervousness or a lack of focus are two of your biggest enemies.

So, how does a stare help this? Some players, including me, make a habit of sometimes during a match just stopping and staring at something for 5-10 seconds. Pick out something in the distance or nearby, it doesn’t matter. Stare at it while clearing your mind of all thoughts. Breathe deeply. Then, after those 5-10 seconds, focus on the match.

You’ll be amazed at how this helps controlling nerves and focus. And at least one top player I know of combined all of this, sometimes staring at his opponent for those 5-10 seconds, especially when about to serve – and using it to clear his mind and focus while sometimes so disconcerting his opponent that the opponent lost his!

Have a problem with a stroke? Need to change the technique? Well, by golly, if you’re like most players, you’ll head out to the table and practice doing the stroke correctly.

No!!!

If you’re like most players, you’ll be struggling to both change the stroke and adjust to the new timing of the stroke, meaning you are trying to do two things at the same time. You’ll find it difficult to repeatedly stroke properly and time the ball, and you’ll likely make subconscious changes to your stroke to adjust to the ball, thereby developing a less-than-perfect stroke.

Instead, repeatedly shadow-practice the correct stroke first. Then, when you (and perhaps your coach) think you are ready and the new stroking technique is mostly ingrained, that’s when you head out to the table and practice with the new stroke. With the new stroke now ingrained from shadow-practice, instead of changing the stroke to adjust to the incoming ball, you’ll adjust your timing to the ball without changing the now-correct stroke.

Imagine trying to learn to hunt from horseback. Would you learn to shoot while on a horse, or would you first learn to shoot and to ride a horse, and then combine the two?

Giddy up!

You can ask three coaches this question and get three different answers. Some say guard against the deep serve and react to the short one. Some say the opposite. Some say guard against both equally.

Make that four different answers, because my answer is, “It depends.”

I once coached a top player who was having trouble moving in quickly to drop short serves back short. I told him to jam the table a bit more, and let his reflexes take over against deep serves. This worked, primarily because the opponent didn’t have great deep serves, and so my player was able to dominate against his short serves.

Recently I coached a player who kept missing against his opponent’s deep, breaking serves. I told him to assume he’d get that serve every time, and just rely on his reflexes against other serves. Even though he only faced that serve about one out of four serves, he went from struggling to dominating against that serve, the opponent’s best serve, and discovered he still had little trouble against the others.

And so, my answer to the question of which to guard against is, “It depends.”

I know of at least one coach and former top player who vehemently says you should always guard against the short serve so you can win the short game battle, and rely on your reflexes against the deep serve. And I know others who say the reverse – and I know that for me, I always had to guard against the long serve, since I always handled short ones better, and needed more time to react to long serves since I usually wanted to loop them with my forehand, since my backhand loop wasn’t so good.

So . . . It depends. It depends on your receiving strengths and weaknesses, and your playing style. It depends on the strength of the opponent’s short and long serves, and how well he follows them up.

You should go into any match prepared for all serves, but perhaps, just maybe, start to guard more against certain serves than others.

So yes, it depends.

Let’s get right to the point – you must lose to improve. Why? Because developing your game means adding new techniques. When you add these techniques, they won’t be developed yet, so they won’t be consistent nor will you be comfortable yet in using them.

Most players have their “comfort zones.” If you stick with your comfort zone techniques, you won’t develop other ones, and so your overall game will stop advancing. Sure, you can improve the shots you already have, but you won’t be adding anything new, and so your development will be hindered and you will never reach your maximum potential.

For example, my comfort zone when I was coming up was to serve and forehand attack, and when the opponent served, to either attack the serve with my forehand (both looping and flipping) or get into a steady backhand rally, often started with a steady but relatively soft backhand flip. Notice what’s missing here? No backhand attack. So, if I could go back to my younger, developing self, I would tell myself to get out of that comfort zone and develop my backhand attack.

Since I didn’t, as I reached higher levels, players got used to my serve and forehand attack game, and I had no real fallback, such as mixing things up with a serve and backhand loop. Or they’d drop my serve short and then quick-push to my wide backhand, and I’d be stuck with either a weak backhand loop, a rushed forehand loop, or just pushing it back. Or they’d just push or flip my serve wide to my forehand and quick block my first attack to my backhand. In rallies, they’d tee off against my steady but not aggressive backhand. All because I never left my comfort zone of forehand attack/steady backhand. (In my defense, I had numerous arm problems that also hindered my backhand attack development, but that’s another story.)

The first thing to do is to think strategically about what new techniques you need to develop. Perhaps discuss it with a coach, top player, or practice partner. Once you have a good idea of what you need to develop, you know what’s coming next – practice, Practice, PRACTICE. And then comes the final part – using it in games. This means losing against players you might have beaten if you stayed in your normal comfort zone. You should look to play weaker players as you develop the new technique, and when you can win there, then use it against your peers. Ideally, do this in practice matches or perhaps in less important tournaments. But the goal is to welcome this new technique into your comfort zone.