If the club is too long or too upright then the heel of the club will stroke the groung first leading to the clubface closing and a pull.

if the club is too short or too flat then the toe will hit the ground first leading the clubface opening and a cut will result.

A way to ckeck is put masking ta[e or duck tape along the bottom of say your 6 iron and practice hitting off a bit of wood or something similar and check what area wears away first.