In his book "How to Play Your Best Golf All the Time", Tommy Armour provides alot of sound advice for improving your game.

The book contains instructions that at first glance may appear to be pretty basic for us so-called more experienced players. Much of the book may have originally been geared more towards beginner and average golfers. However, on closer inspection the reader discovers that even the seemingly basic stuff contains hidden jewels of wisdom. What you notice is a flow of well thought out ideas which form a fundamental basis that is absolutely necessary if you want to play golf well.

Here are my favorite quips:

• Action before thought is the ruin of most of your shots.
• When you miss a shot, never think of what you did wrong. Come up to the next shot thinking of what you must do right.
• Make up your mind before your backswing starts, then let your muscles do the work.