What do you think is the secret to practicing the presence of God?
It sounds like you’re referring to a currently popular book called “Practice the Presence of God” by a 17th century catholic monk. I have only read a summary the book, which sounded a lot like a commentary on Phil.4:4-7. If so, then the secret is to begin applying Paul’s advice.
“Rejoice in the Lord always. I will say it again: Rejoice! Let your gentleness be evident to all. The Lord is near. Do not be anxious about anything, but in every situation, by prayer and petition, with thanksgiving, present your requests to God. And the peace of God, which transcends all understanding, will guard your hearts and your minds in Christ Jesus.”
Rejoicing over everything that happens, trusting God in every situation, and maintaining an open channel of prayer and thanksgiving are all things anyone can start doing immediately. When we do, we’ll be “practicing the presence of God.”