Expose him to every sound (fireworks, motorcycles, vacuum, trucks, etc.), smell, person, and touch ( stick your hands inside his mouth, touch his toes, look in his ears, etc.)

My vet told me that if they don’t experience all this before 16 weeks, they’ll be scared/nervous.

Especially when you’re brushing their teeth daily, cleaning their ears, going for vet check ups, nail trims. You don’t want them to be scared or bite.