Ordinary thinking has its place in daily affairs. However, if you let your thoughts guide you unconsciously, they will mislead you often. Verify this fact for yourself by paying attention to your thoughts throughout the day and noticing when they are misleading or causing you to suffer. Once you have observed them for any length of time, I know you will agree; if you ignore them, they will always convince you that they are truthful and correct, even the rambling that occurs quietly in the background, which is what you want to notice.
The key is not to try and stop the thoughts; this is impossible and will only lead to more anxiety, frustration, and suffering. You only need to notice them and then let them go. It sounds simple to do but requires commitment and persistence. Notice when they have distracted you once again and let them go. Do this for the rest of your life as best you can, whenever you can. You will notice the peace you have been seeking was there all along because that is your natural state of being underneath all the meaningless and unhelpful thoughts.