The Differences Between “By” and “With”
Both prepositions can be used to show how something is done.
‘By’ can be followed by gerund (-ing form):
He improved his English by reading novels.
You can change the look of that room by redecorating it.
‘By’ is followed by a noun in combinations referring to the means of transportation or combination:
‘With’ is used when tools or parts of the body mentioned:
I opened the Pepsi with a bottle opener.
He pushed the door with his foot.
Note: ‘by hand’ means ‘handmade’, ‘made by a person, not by a machine’:
She made the pie dough by hand.
Compare to: The mother touched the girl’s forehead with her hand.