The only thing you need to do is meditate, this will focus your mind.
Meditation is not a belief system and it is not anything to do with religion it is quite scientific.
A very simple formal technique is to take 10 minutes with your phone off, TV, radio and music off and sit somewhere comfortable on your own. As you relax in the silence begin to put your attention on your breath as you breath normally. Your attention will go off your breath and when it does and your mind begins to distract you just gently pull your attention back to your breath. Carry on doing this for 10 minutes each day.
It is not in the moments that you are meditating that you feel the focus but afterwards during your life. This method of beginning to get mastery of the mind is what is important and when you consciously put your attention on the breath you are stopping the mind from having power over you. You are not the mind but are a deeper prescence that lies deep within, by meditating you are building the strength of this deeper part - your higher self which will give you peace, wisdom and strength in your life. Meditating is not a time for thinking. Focused thinking will come after meditating.
Within a month of using this method your life and your attitude and mastery will have changed drastically.