"My sponsor keeps telling me to "stay in the moment, live in the now," but is never able to tell me how to do this - can you help?"
The only way I have found it possible to do this with any sustained success reqires that I first become aware of my internal dialogue - what's going on inside my own head. Am I worrying about the future? Chewing over the past? Am I rewriting an argument, making my part vastly more intelligent and mature than it was at the time? Am I projecting? Having imaginary conversations?
When new to Al-Anon, I was impatient with any suggestion that I try to be aware of my thoughts as they floated through my head; I didn't believe it was possible to change what went on up there, so couldn't see the point of the exercise. I did it anyway, under duress, and with much moaning and complaint.
It was illuminating to discover just how negative was my thinking.
So, try to be aware of your internal dialogue. When you catch yourself thinking about the past, or projecting into the future, bring your mind back to the present. You could try the exercise of describing to yourself what you are doing in the now - "Now I am washing dishes. I'm in my kitchen standing at the sink, with my hands in hot sudsy water, cleaning up after a meal." (For those of you who will say, "But I've got a dishwasher, I don't wash dishes!" - describe to yourself the loading of the dishwasher, and the general clearing up.)
The point of that exercise is to anchor yourself in the present moment, by keeping your mind occupied with what you are doing now. You may find that this is like trying to grasp smoke when you first try it, because it's a hard habit to break when we live anywhere but in the now.
I might tell myself, "No projecting, no recreations." and turn my mind again to what I'm doing right this minute. If you find music helps you to stay in the present moment, use that. Reading works for me, as does creating - sewing or painting.
Your sponsor, as are we all, is fallible, and they may have difficulty describing how they do this - ask other people in Al-Anon, and be open-minded and willing enough to try their suggestions, no matter how silly they may sound. Be gentle with yourself, this isn't easy, but it's like anything else, we get better the more often we practise.