Isolate him
So he thinks the world is a strange place.
Soothe him whenever he is frightened or aggressive
So his worrying is rewarded.
Respond to his every whim
So you teach him early and often that the world revolves around him.
Refuse to neuter
So he has maximum testosterone in his system at all times making all sorts of problems more likely including several types of agression.
When he pulls on lead, follow him
So he hauls hard on lead and is out in front ready to bark/react to anything he sees
Whenever he struggles, let him go immediately
So he learns to fight and fight hard with you and gets what he wants for doing so.
Tease him “for fun”
So he learns you cannot be trusted
Allow others to hassle him
So he learns that he has to protect himself
Skip all training
So he has no shared communication with you and all you have is reaction to attempt to control him with.
Yell at, swat and frighten him to “control” him
So he never learns to see you as a trusted leader, only as an unstable housemate
Tell him “NO!” a lot
So he learns to tune you out or fear you or some combination.
Keep him away from other dogs or pair him up with bigger, rougher dogs
So he can learn to be frightened of and/or defensive around other dogs,