It's all about getting your body/mind used to a certain state of mind. If you are constantly worried/anxious/impatient/etc., that will be your natural state of being and what your body/mind will naturally return to after you experience different states - such as calmness/confidence/etc.
So change your natural state of being by actively changing the way you think and feel. Practice meditation/relaxation techniques - rational thinking techniques (such as CBT excercises), acceptance (accept that you're this way, don't feel bad about it, and accept how much work/dedication you are willing to put into improving this and be glad about it) and thankfulness (consciously
realize what you have in your life that you are thankful for - such as health, a job, healthy family, a good friend, a good lover, etc.) These are the things that have helped me to slowly change my natural state of mind from that of an anxious/paranoid one to a chill/clear-thinking/carefree one

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