The best moment to practice meditation is when your mind is calmed down and you are most at peace. Do not try to NOT think about anything - That means, that if you are thinking about “not” thinking, you will probably think about something and start a dialogue in your head. Instead of that (and this is the key) practice witnessing. A dialogue only starts from your senses, etc. if you hear a sound of a car or hear a door, then you start a dialogue. practice witnessing means that you only witness the sounds or the thoughts that are coming into your mind, without questioning. just let them pass.