Paul Fromont writes about the essential ingredients for spiritual formation. I like the basic equation that he offers:
Triune God + key people + opportunities + space + regular practices + life experiences (+ & -) + key txts + thin places + technology = spiritual formation
Having all of those in line doesn’t “guarantee” formation like some sort of formula. But I think each aspect is necessary for a life of intentional apprenticeship to Jesus.
I think I would probably add a couple of other aspects as well. First would be one’s attitude (love the Lord your God with all you heart, mind, soul & strength and your neighbor like yourself), but perhaps that’s assumed into the entire equation of pursuing spiritual formation.
I would also add something about engaging one’s entire humanity as Dallas Willard discusses in Renovation of the Heart. As embodied beings, spiritual formation involves my mind, feelings, body, will, and relationships. But this may be redundant and assumed in the specific aspects already in the equation.