In addition to what you shared above (devotion to the Word and sincere prayer), I experience intimacy in my relationship with God when I fast. Not just from food but other stuff like social media.

I however get a deeper depth in my walk with God when serving other people in ways He commands. Not in some extraordinary way, but in the simple mundane things like helping a merchant gather her fallen wares or reaching out to new members in my Christian community.

But like you said, there’s no hard formula. It’s an interpersonal relationship and takes time, commitment and trust.