You will succeed with practice — and that's all it takes — patient, kind practice. You need to be kind to yourself because getting frustrated or angry adds more turbulence and further disturbs your mental content.
Probably you will notice you cannot concentrate very well unless you are aware of your character flaws and are striving to do something about them. Often, when you try to concentrate, your character "shortcomings" will float — or flash — into your mind, unless you have the peace which comes with the effort to be a better person: a kinder, more constructive, efficient, responsible human being.
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With practice, you find it is not too difficult to choose the content of your mind. That is to say, you find you can borrow your own mind at times, borrow it from oblivion and wild turbulence, to do something constructive and pleasant with it. This practice alone greatly reduces the "worry time" that most people clock into their lives.
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