Extreme coupon-ing

I see a lot of friends on my Facebook posting pictures of crazy shopping trips for baby supplies and other household items like tampons and body soap etc. Where they save close to 100 dollars. I need someone to teach me there ways. When I was younger ( I mean like 5 or 6) I used to help my grandma with grocery shopping and she'd always take coupons. But I always saw limits saying "up to 10" etc. I just want to know how these people are getting 15 bottles of body wash and 8 boxes of diapers!!! Teach me please!!