Look first at checks, captures, and moves that attack the opponent's pieces.

Always check - it may be mate.

Passed pawns must be pushed

A knight on the rim is dim

The ten principles of Steinitz are worth following.

Get a good rest before playing tourneys 

Don't blunder

The mid-life crisis occurs when you are frustrated by your failure to achieve mastery of chess when young, and forsee no chance of achieving mastery in your dotage.

Every chess match is a potential mate!

Haha good luck!

let them move then you move

God bless you my friend

Attack the King's house! (James Bond, please note, I'm talking chess here...)

"Only he who never plays never loses." - Anatoly Karpov
"Every chess master was once a beginner." - Irving Chernev
"In life, as in chess, forethought wins." - Charles Buxton
"It's always better to sacrifice your opponent's men." - Savielly Tartakower
"Even a poor plan is better than no plan at all." - Mikhail Chigorin
"When you see a good move, look for a better one." - Emanuel Lasker
"One bad move nullifies forty good ones." - Bernhard Horwitz
"Hard work is a talent." - Garry Kasparov
"Every pawn is a potential queen." - James Mason
"Pawns are the soul of chess." - Francois-Andre Philidor
"A good player is always lucky." - Jose Raul Capablanca 
"Only the player with the initiative has the right to attack." - Wilhelm Steinitz
"If your opponent offers you a draw, try to work out why he thinks he's worse off." - Nigel Short

And a bonus:

"There are two types of sacrifices: correct ones and mine." - Mikhail Tal

"The biggest pleasure in life? To stay always active!" - Karpov.

Perhaps we need a stupid things chess players say thread, you could start it with: 

"Girls just don’t have the brains to play chess" - Nigel Short

He was quickly checkmated with some wise words from Amanda Ross, who runs the Casual Chess cafe in London:

“Incredibly damaging when someone so respected basically endorses sexism”.

“Judit Polgar, the former women’s world champion, beat Nigel Short eight classical games to three in total with five draws."

“At least this resolves the age-old debate as to whether there’s a direct link between chess-playing ability and intelligence. Clearly not.”

Amanda's comment uses subtle irony, I don't see it as at all silly. Dismissive maybe. Nigel deserved dismissing, in this instance. His "If your opponent offers you a draw, try to work out why he thinks he's worse off." is quite wise though!