What does your mind dwell on daily? Perhaps a movie or television show you watched or are watching. Maybe a book you are reading. Perhaps it is dwelling on problems. To get your mind off bad stuff you have to intentionally think on good stuff. To think on good stuff you have to make a habit of focusing on good. That is harder to do if in your spare time you fill your mind with junk.
A mind controlled by the things of the spirit thinks on good things. A mind controlled by things of the flesh will dwell on wrong things. You must make it a point to fill your mind on what is good, uplifting, pure, peaceful, and loving. Don't get up and the first thing you do is to start worrying. Stop if you do that and start praising God and praying instead. Be careful what you choose for 'entertainment' if the shows are full of immorality, swearing, killing and the like. Better to turn off the television.
Don't allow Satan to control your thoughts and make you become anxious. Talk out loud to him and say "Satan you have no power over me. I am a child of God. I refuse to think wrong thoughts.Be gone and leave me alone." Try it and see if you do not feel better. Before you know it you will have a mind fest of pure, wholesome, and positive thoughts and the other kind will be just a memory.
PRAYER: Lord Jesus I purpose in my heart today to think on things above not my problems down here. I choose to think good thoughts and keep you in them. In Jesus' name. Amen.