Here are 2 ways to take your thoughts captive:
Taking your thoughts captive simply means gaining control over what you think about. Here is a great article from crosswalk.com
“Accept responsibility for your thoughts. You have the ability to exercise control over your thoughts. God warned Cain to focus his mind on the right things, but Cain chose to think about the wrong things – anger and jealousy – which led to his murderous actions. Are you willing to admit that you can, with God’s help, regain control of your thoughts – and think enabling thoughts instead of disabling ones? 2. Choose to focus your thoughts on the right things. We are to think about those things that are “true, noble, right, pure, lovely, and admirable” (Phil. 4:8). When we think about those things, God promises to give us His peace. What a contrast that is to the thoughts of millions of people today. Don’t look to a movie, TV show, or how-to formula to accomplish this for you. It takes personal discipline and commitment.”
Consider praying: “Father, show me how to change the way I think.”
Think only pure thoughts that you can think about, as if God is watching (He is). Always be praying about running from what you can’t look at/think about.
Every time a wrong thought pops into your head consider praying: “Father, help me to take this thought captive. I praise you today. Please give me new thoughts.”