without quoting anyone and writing this very quickly:
-i have "successful" amounts of head on the vast majority of my beers
-keep everything clean/free of oil/dirt (a KISS system helps doing this
)
-i have tried special/stepped mashes over time and i can distinctly remember the last one i did was a hochkurz and the head on that beer was abysmal.
-i do single infusion mashes at about ~150F and i generally get good head depending on the grist
-no need for crystal/carapils/flaked oats/barley. its so tempting to say "they help" in size/stability but the beers i've made with some of the most impressive heads have been truly 100% base malt (including acidulated malt)
-more hops result in larger head in my opinion
-frankly, the higher the CO2 volume the more enhanced a decently stable head will be. the "secret" to the head in a lot of belgian beers imho is becuase they have 3.5+ vol CO2. it's a no-brainer.
i dont care too much about head anymore because its just me drinking my beer, and i've been doing low co2 level beers for a while now
edit: lol just checked and duvel is apparently 4.25 vol CO2. that is insane, but that is kind of the beer i think of when it comes to "massive head every time". there is no mystery to it. if duvel was carbed to say 2.0, i would imagine it would visually look like a typical pale lager.