Originally, Shinto lacked any set doctrine or teaching method, which meant there was no need to differentiate Koshinto and folk beliefs in Kozukuri (baby-making) or Yorigami (god-summoning) from the rest of Shinto, including Shrine Shinto; if one constrains oneself to unearth the similarities that can be discovered in the above-mentioned actions, the only one that comes to mind is the concept that one must "purify, rectify, and beautify" one's heart.
本来は神道とは、教義・教則のないものであり、古神道や「子作り信仰」や「寄り神信仰」などの民間信仰と神社神道を含め神道をわけ隔てる必要も無く、強いてその本質の共通性を上記の行為から汲み取るとすれば、己の心に対し「清く・正しく・美しく」あれということでしかないだろう。