I find it difficult to live in the moment or go with the flow as i am reminded of the sense doors and hence am guarded in the present to not to be totally involved in the moment and I miss the flow or to experience the moment as it is. I am trying to follow the zen and the middle path. How does one practice being in the present ?
"Living in the moment" isn't a practice, but a result. It's another word for the mindfulness or wakefulness "muscle" that develops as you do your practice. So if you don't feel it, don't worry about it.
Follow the instructions for your particular practice, and you will feel your "muscle" for living in the present moment gradually strengthening in your daily life. For example, as time goes by, you'll notice that it is easier to be concentrated in everyday situations, or that you are more and more resilient in recovering from strong emotions.
It isn't really "you" living in the present moment, anyways. Your awareness is always living in the moment as it is. You don't need to correct your awareness. If you try to live in the present moment, then you'll merely be constantly trying to do two things at once
When you watch the sense doors, it's your non-present "self" that practices turning itself toward a true present phenomenon, and it does it over and over again. It's the only tool you have, so it's normal if you feel that doing this is not in harmony with the "true" present moment. But it is the right way to develop the skill of returning to your awareness more and more often, so that it becomes more and more automatic.
On seeing a form with the eye,
one investigates the form that is the basis for mental joy,
one investigates the form that is the basis of mental pain,
one investigates the form that is the basis of equanimity.
the latent tendency to lust reinforced by being attached to pleasant feelings;
the latent tendency to aversion reinforced by rejecting painful feelings;
the latent tendency to ignorance reinforced by ignoring neutral feelings;
So to experience the moment what ever sensation from the sense door be equanimous noting the impermanence / arising and passing of the sensation arising due to the sense door. This is the way to be in the present moment.
The middle path in essence is to avoid extremes, which not tied with the goal, and cultivate your mind towards liberation. See: Middle Path, Middle Way and middle-way for more elaborate details on the middle path.
You can try to first practise the mindfulness meditation taught by Yuttadhammo Bhikkhu, including the sitting meditation and the walking meditation. There is the text for this here and the YouTube video playlist here.
After that, you can slowly incorporate it into daily life.
In Chapter Six, he says:
Further, one can apply the same technique to any small movement of the body – for instance when bending or stretching the limbs, one can note “bending” or “stretching”. When moving the limbs, “moving”. When turning, “turning”, and so on. Every activity can become a meditation practice in this way; when brushing one’s teeth, “brushing”; when chewing or swallowing food, “chewing, chewing”, “swallowing, swallowing” and so on.
When cooking, cleaning, exercising, showering, changing clothes, even on the toilet, one can be mindful of the movements of the body involved, creating clear awareness of reality at all times. This is the first method by which one can and should incorporate the meditation practice directly into ordinary life.
Another teacher who has produced good material on this subject is Thich Nhat Hanh.
By not getting caught up in thoughts. If you notice that you're involved in thinking, unless it's necessary to the task at hand, let go of it. Come back to the here and now.
Keep repeating this practice every time time you notice you're lost in thought, ten, a hundred, a thousand times a day. Keep coming back to the here and now.