Kathleen at Fashion Incubator posted a grading quiz a couple of days ago that illustrated the grade of an infant polo shirt. Even if grading is beyond you it would be worth looking at the images. These are really good pictures of graded nests - graded pattern pieces stacked on top of each other. Eventually, your patterns need to be graded and nesting patterns is one way to check the grade.
Even though I have been grading patterns for the last 10 years, I am still learning about grading. I was partially trained by an employer, but mostly self-taught. I have been re-learning how to grade using different methods and it has been a struggle. My goal is to better understand grading principles and to refine the skills I already have. The process of grading is not as hard as it looks. Often it is just like following a recipe with step-by-step instructions. Understanding grading principles and why certain methods developed takes time and experience. I wish I could sit at the feet of a master and absorb their wisdom.
BTW, if you haven't voted in my bib poll, please do!