I can’t speak enough about positive thoughts and mental imagery. As you train (or with anything in life) see yourself, your physique, the muscle you are targeting as you wish to be and as you know it to be will happen if you put the work and effort in. Having this “proper mental attitude” is what separates those who succeed and those who fail.
“It is my honest opinion, based on thirty years of bodybuilding experience, that you cannot fail to make gains if you see yourself as you wish to be. Changing your workouts around constantly is not the answer, but a proper mental attitude is. Never doubt or lose sight of the fact that you WILL reach your goal.” Vince Gironda on having the proper mental attitude