What is some good advice that Mrs. Jong offered Meimei in "Rules of the Game"?

Waverly’s mother advises her “strongest wind cannot be seen” and tells her to always learn the rules in a foreign country.

Waverly’s mother’s advice may not be in perfect English, but it is good advice just the same.  Her point is that if you stay under the radar and work for a goal, you are more likely to accomplish that goal. 

I was six when my mother taught me the art of invisible strength. It...

Waverly’s mother advises her “strongest wind cannot be seen” and tells her to always learn the rules in a foreign country.

Waverly’s mother’s advice may not be in perfect English, but it is good advice just the same.  Her point is that if you stay under the radar and work for a goal, you are more likely to accomplish that goal. 

I was six when my mother taught me the art of invisible strength. It was a strategy for winning arguments, respect from others, and eventually, though neither of us knew it at the time, chess games.

This is Waverly’s approach to chess.  She is good because she practices and works hard, but she looks cute and little and no one expects her to be a chess champion.  Instead of worrying about her age, Waverly uses her age and size as an advantage.

When the family gets a chess set, Waverly’s mother at first wants to throw it away because the woman who donated it did not want it.  If she did not want it, Waverly’s mother did not want it.  When her children want to play with it anyway, she agrees to let them but tells them they need to read the rules carefully.

"Every time people come out from foreign country, must know rules. You not know, judge say, Too bad, go back. They not telling you why so you can use their way go forward. They say, “Don't know why, you find out yourself. But they knowing all the time. Better you take it, find out why yourself."

This is good advice.  When you go to a foreign country or play someone else’s game, you need to know the rules or they may be able to get something over on you.  Whatever you are doing, you need to make sure that you are aware of every aspect of the situation.