Very hard to live in the moment.
I find the best way for me to live in the moment is for me to break the train of thoughts when my mind begins 'projecting' negatively into the future, regressing backwards, or when my mind tells me it is okay to use.
When I start having 'out of the moment' thoughts:
* As soon as I realize I am 'out of the moment' I begin reciting the 12 steps in my mind.
* Or I start singing a song, either out loud or to myself.
Whatever it takes for me to break my train of thought. Once I break the train of thought I usually always get back on an even keel.
In essence, I 'force' my mind to think about something else.