You cannot have a positive life and a negative mind. 

Joyce Meyer

Very little is needed to make a happy life; it is all within yourself, in your way of thinking. 

 Marcus Aurelius

Your work is going to fill a large part of your life, and the only way to be truly satisfied is to do what you believe is great work. And the only way to do great work is to love what you do. If you haven't found it yet, keep looking. Don't settle. As with all matters of the heart, you'll know when you find it.

Steve Jobs

Once you replace negative thoughts with positive ones, you'll start having positive results. 

Willie Nelson

By three methods we may learn wisdom: First, by reflection, which is noblest; Second, by imitation, which is easiest; and third by experience, which is the bitterest. 

Confucius

Success is not final, failure is not fatal: it is the courage to continue that counts. 

Winston Churchill