Understanding GFSI Food Safety Standards

I recently started learning more about food handling after helping a friend with a small food business. During my research, I came across gfsi food safety and realized there is much more involved than simply keeping food clean and properly stored. Different processes can help reduce risks and improve food handling at each stage. I am still learning about the subject, so I wanted to ask others here. What was the most useful thing you learned about GFSI standards? Are there any basic points that beginners often overlook?