You can use this as a reminder any time things aren't going the way you'd like them to or whenever you're afraid of your current circumstances. I love this! It means you really do have control of much more in your life than you realize. If you can conquer fear by just changing your thoughts, then think about the power you have! Think about what dramatic changes you can make in your life.
The key here is to make certain that you can remember this thought any time you start to feel the fear - fear of anything.
Then you have to make sure you're projecting the correct thoughts to the Universe. This means that you want to phrase your thoughts correctly. If you say "I am no longer in debt", you are still focused on debt. Instead you want to say "I am prosperous, I have paid off everything I owe AND with an abundance of money remaining" and say it with feeling.
This may seem difficult to do when you're experiencing fear but that's why remembering that you can control this feeling and bring the Universe back to your side needs to be done as soon as possible. The longer you experience a feeling (whether it's fear or joy), the more vibration it generates, the more momentum it gathers and the harder it is to turn around. I start reversing activity as soon as I start thinking that nudging thought that leads to fear. If you watch TV (I don't because I don't want to be constantly fighting the negativity and its effects on my subconscious mind), and you see an article about crime in your area, you may start to worry about whether you locked your doors and windows and whether that's sufficient security, etc. As soon as any of those thoughts start to roam around in your brain, change your thoughts and partner with the Universe - "I live in a wonderfully safe location and house and am protected by the Universe". Say this and other positive thoughts you have over and over again until you no longer feel the fear in your gut.
Repetition is key to this. You repeat the positive thoughts as many times as necessary to lessen your anxiety. Use this phrase too and edit it to fill in the appropriate parts for yourself and your situation - "Nothing and nobody can interfere with my health, well-being, peace of mind and prosperity, not even myself!" Make sure that you include that last part because most often it is ourselves that keep us from achieving what we set out to.
Try these techniques next time you are starting to feel fear.