Hit rocks with a shovel or axe
Use a shovel to dig two holes behind you before hitting rocks to prevent knockback
Eat fruit only if you want to break rocks for other materials
Use a stone axe or regular axe, not a flimsy axe, for rock hits
Hit each rock up to 8 times quickly to get more materials
Check all rocks on your island every day
Use Nook Miles Tickets to visit mystery islands and hit their rocks
Use the Money Rock for extra materials, including iron nuggets
Use the Rock Respawn method by breaking rocks and waiting for them to reappear the next day
Buy iron nuggets from Nook’s Cranny if available in your version of the game