In the children’s classic The Secret Garden by Frances Hodges Burnette, Mrs. Burnette gives us these observations: 

One of the new things people began to find out in the last century was that thoughts, just mere thoughts, were as powerful as electric batteries, as good for one as sunlight is, or as bad for one as poison is. To let a sad thought or a bad thought get into your mind is as dangerous as letting a scarlet fever germ get into your body. If you let it stay there after it has got in, you may never get over it so long as you live.

Thoughts have a great impact on how we live, whether we’re enthusiastic or depressed, whether we enjoy success or experience failure, whether we enjoy spirituality or suffer from a lack of it. Proverbs tells us that as a man “thinketh in his heart, so is he” (Proverbs 23:7). To paraphrase that slightly, it would be very accurate to say that, as a man persists in his thinking, so he will become. There is that kind of power in thoughts.

How do we control this awesome power? How do we use it not only to prevent and defend ourselves from the possible detrimental and  influence of bad thoughts, but also to utilise this great power to achieve the fulfilment of life’s purpose for us? 

You will learn that your moods, your attitude toward daily living and toward other, are in a large measure regulated by your thoughts. To a large degree, you can control whether or not you are happy today or unhappy, whether you're enthusiastic about your possibilities or depressed and negative. You'll discovered, as perhaps we have, that if you allow yourself to slip into a pattern of negative, depressed thinking—although your circumstances have not changed—you can make yourself very unhappy and make your prospects seem extremely dim. You can reverse that almost as easily by replacing those thoughts with others that are constructive. 

Lets relate another sentence or two from Mrs. Burnette’s observations in this same children’s classic we referred to above. She tells about a boy, Colin, who is one of the interesting characters in this story:

So long as Colin shut himself up in his room and thought only of his fears and weaknesses and his detestation of people who looked at him and reflected hourly on humps and early death, he was a hysterical, half-crazy little hypochondriac who knew nothing of the sunshine and the spring and also did not know that he could get well and stand upon his feet if he tried to do it. When new, beautiful thoughts began to push out the old, hideous ones, life began to come back and his blood ran healthfully through his veins and strength poured into him like a flood. His scientific experiment was quite practical and simple. There was nothing weird about it at all. Much more surprising things can happen to anyone who, when a disagreeable or discouraged thought comes into his mind, just has the sense to remember in time and push it out by putting in an agreeable, determinedly courageous one. Two things cannot be in one place. Where you tend a rose, my lad, a thistle cannot grow.

TRULY,  ‘thoughts are things,’ and powerful things at that, when they are mixed with definiteness of purpose, persistence, and a BURNING DESIRE they can then be translated into archiving that which you desperately seek. When you really DESIRES a thing so deeply that you are willing to put at stake your entire future on a single turn of the wheel in order to get it, you are sure to win. 

One of the most common causes of failure is the habit of quitting when one experiences temporary defeat. Everyone is guilty of this mistake at one time or another. Before success can comes in your life, you are sure to encounter temporary defeat, and, perhaps, some failure. But life is strange, and often imponderable! Both successes and the failures have their roots in simple experiences that we go through on a daily base. One of the main weaknesses of human race is the average man's familiarity with the word ‘impossible.' Success comes to those who become SUCCESS CONSCIOUS. Failure comes to those who indifferently allow themselves to become FAILURE CONSCIOUS. 

Millions of people look at the achievements of Henry Ford, and envy him, because they think it was a good fortune, or luck, or him just being a genius, or whatever it is that they credit Ford's fortune to. There is a story told by Napoleon Hill in a book he wrote about how Henry Ford archived things: 

A few years back, Ford decided to produce his now famous V8. He chose to build  an engine with the entire eight cylinders cast in one block, and instructed his engineers to produce a design for the engine. The design was placed on paper, but  the engineers agreed, to a man, that it was simply impossible to cast an  eightcylinder gas engine block in one piece. Ford said, ‘Produce it anyway. ’ ‘But,’  they replied, ‘it's impossible!’ ‘Go ahead,’ Ford commanded, ‘and stay on  the job until you succeed no matter how much time is required.’ The  engineers went  ahead. There was nothing else for them to do, if they were to remain on the Ford  staff. Six months went by, nothing happened. Another six months passed, and still nothing happened. The engineers tried every conceivable plan to carry out the  orders, but the thing seemed out of the question; ‘impossible!’ At the end of the year Ford checked with his engineers, and again they informed him they had found no way to carry out his orders. ‘Go right ahead,’ said Ford, ‘I want it, and I'll have it.’ They went ahead, and then, as if by a stroke of magic, the secret was discovered. Mr Ford DETERMINATION had won once more!

You are the Masters of your own Fate, the  Captains of your Souls, because you have the  power to control your thoughts.

"Our brains become magnetised with the dominating thoughts which we hold in our minds, and, by means with which no man is familiar, these ‘magnets’ attract to us the forces, the people, the circumstances of life which are in harmony with the nature of our dominating thoughts." Napoleon Hill