When we say "God with us", we are speaking of the present at all times. We are not concerned with the "ought tos" of the past or the "what ifs" of the future.
God is with us right now. When we listen to Jesus speak of God, it is in the context of God being where we are and when we are.
Our minds make this difficult because it is always dragging us away from the moment. This is why prayer is so necessary in our day to day, because it is a discipline that drags me back into the current moment where God is. Prayer makes me be present now with my mind and heart. It also makes me listen to the One who speaks to me where I am, when I am.
What does that look like practically?
Henri Nouwen suggests, "The most fruitful way--in my experience--is to take a simple prayer, a sentence or even a word, and slowly repeat it."
This could be any of the common breath prayers, a passage, or a word that speaks to the heart of hearts within me for the day. When we are faithful to this discipline, even if it is ten minutes at the beginning of the day, I gradually begin to recognize a space within myself where God dwells, and I am invited to dwell throughout my day. I can focus ten minutes on that inner space, and then I can return to that place for a moment throughout my day when I need to at a moment's notice.