Having made some money trading stocks and shares, I have had lots of time on my hands to play golf. Once I had got down to a 10 handicap and was able to properly enjoy my game, I found that when I used the same mental training techniques for golf that I used whilst trading, my game quickly stabilized and my scores plummeted into the 70's.
I give you the following, purely as my personal interpretation of how ideally one should start to try and approach the whole "mental" aspect of the game. Now I am a low handicap, I realise with hindsight, that it was the mental aspect of the game, that once grasped, quickly allowed me to evaluate situations clearer and faster, and then judge my actions more rationally and easily. A large subject to attack admittedly, but even just a glancing blow at the surface of this part of the game/brain (!) quickly allows you to see the importance of having clear mental processes when making decisions in golf .......and ultimately in your life!