The ability to place a horses feet says a lot about the relationship. Horses are precious about their feet (and they should be) so being able to control them goes a long way in building trust.
But… doing things for the sake of doing them can actually have a negative effect. Don’t desensitise your horse to objects - sensitise them. That is, have them check in before stepping up or over something. Not only does it keep you safe, it builds relationship.