Knowledge is like ammo. You want to gather as much as you can but don’t give up any to others. Balancing that will be an everyday affair.
Be the person that says hello to others. You may be in a hurry but an additional 2 or 3 minutes can pay dividends.
A fruitful conversation is a two way street. If asked just give a general answer: “Where do you work? Oh, I am a teacher/garbage man/street worker.” will put your subject at ease and then you can start asking them stuff. So many people go through life not telling anyone, except family, about what they do for a living.
Most conversations are about: job, personal health, health of family. Keep your questions to these categories and you will be surprised what you learn.