Strongest knuckles on your hand. First two knuckles can be lined up with forearm bones to increase strength. Target is your opponent's solar plexus. A soft blow to the solar plexus can knock the wind out of someone. The philtrum is the dent directly below your nose.
Punches are too high.
Middle punches are at shoulder level instead of solar plexus. Rising punches are at forehead level instead of philtrum. Palm faces up. Thumb is wrapped around fist. Fist is held against rib cage.