To become a positive person, you must put positive things into your mind.  There is no other way to create a positive mind.

You can change the way you think and feel by changing what you say when you talk to your mind.

If you want to change the way you feel, you are going to have to change your inner dialogue.  You are going to have to talk to your mind in a different manner.  You must monitor your self-talk and make sure it's positive, and if it's not positive, you must change it.  This isn't optional. If you don't make your self-talk positive, there is no way you are going to win the battle of the mind.

The wheel of change always turns in the direction of what you put into your mind.

What you put into your mind is critical.  The only way to become a positive person is to put positive things into your mind.  You can make your mind as positive as you want if you are willing to put positive things into your mind.

People who have a genetic predisposition to mood disorders have an even greater need to fill their mind with positive things.  People who have an inner vulnerability predisposing them to depression need to be especially careful about what they allow in their mind.  If  they fill their mind with toxic waste, they will become depressed.  For these people, the price of a positive mind is eternal vigilance.  They must continually stand watch on the door of their mind to keep it from filling up with toxic waste.  They must become proactive and adopt a program in which they spend time each day putting positive things into their mind.

Excerpt from :

Zero Tolerance To Negative Thinking : Good-by Depression - Hello Positive Mind

David J Abbott M.D.