How does one maintain spiritual mindfulness and awareness of the present moment while being faced with daily struggles and challenges?

To maintain spiritual mindfulness and awareness of the present moment, while being faced with daily struggles and challenges, first of all, we shall attain Self-Realization.

Currently, you believe yourself to be the mind and body complex, isn’t it? Therefore, you experience everything that the body and mind does and feel? But when the Enlightened One puts in a line of demarcation between the Self (Soul, Aatma) and the non-Self (the body-complex, Anaatma) and helps you attain Self-Realization, you realize the Self i.e. you understand who really am I. Then, the Self and the non-Self remain in their respective state.

“Worldly life is based on action and spiritual life is based on Knowing. One carries out the activity, whereas the other keeps ‘Seeing’ it. The ‘doer’ and the ‘Knower’ can never be the same, they are always separate. They were separate, they are separate, and they will remain separate.”
- Param Pujya Dada Bhagwan

After Self-Realization, the Enlightened One teaches how one can maintain spiritual mindfulness and awareness of the present moment. He says:

One who carries out the activity, allows him to work through the daily struggles and challenges, without any interference from your side. and You remain in the awareness of the Soul and keep seeing. Then, you are said to have remained in the present moment.

When one activity finishes and the other begins, one is focussed on that other activity, and as the third activity begins, one is in that activity then. And in that, we know whether the activity is being carried out properly or not. Thus, we are in the present only every time. One carrying out the activity moves from one struggle / challenge to another and we see the one carrying out the activity, so we are said to be in the present. The external activity will keep changing. For instance, when one is eating, one is focussed on eating. Now while eating, if one gets busy talking, then one is not in the present moment, because the activity being carried out is that of eating; however we are not seeing that, and we started seeing something else, “Oh, it was nice satsang, today many people were there in the hall.’ So, while the body is eating, the consciousness is somewhere else, in the hall. There we have lost the awareness of the present moment. Present means in that moment, we (the awareness) remain present there and then.

He further explains illustrating with an example:

Suppose you are talking to your neighbour, what should I do? I will keep seeing. And when you finish talking, I can say, “Sir, would you listen to me?” Likewise, there are three: 1. Work, 2. One carrying out the activity, and 3. You (the Soul, the Self). You are in your place, work is in its place, and the one working on it is in his respective place.
When one is absorbed into the work, say within, “Go, do your job well with full concentration.” One has to concentrate on his work; in case the mind, intellect, consciousness and ego are not focussed on the work, then instead of 7, 17 may get written, and instead of 17, 2 may get written and it would create a mess!. So allow the one, carrying out the activity, to focus on the activity, “Get absorbed in the work, don’t mind.” It’s because the ego has decided to complete this task. And once the task is completed, you, as a Soul, take the charge, “You finished that? Ok, now let’s move onto the next.” Then, you are said to be in the awareness of the present moment! And where you miss, reset the awareness once again.