Continuous attentiveness will only come with long practice. If you are truly watchful, each thought will dissolve at the moment that it appears. But to reach this level of disassociation you must have no attachments at all. If you have the slightest interest in any particular thought, it will evade your attentiveness, connect with other thoughts, and take over your mind for a few seconds; and this will happen even more if you are accustomed to reacting emotionally to a particular thought