Patting dry the squid will help to cook it faster and prevent it from becoming chewy.
The scoring of squid should be done on the softer side (the inside of the tube). If you feel resistance in your knife, flip and try the other side to be sure.
Squid is best as fresh as possible. Undercooked is better than overcooked as it will become tough.
Fresh seafood tastes better. Shop for fresh, sustainably sourced Squid.