For those who have made the decision to learn coin grading, they need to be aware that this is something you commit to for life. There is no exact science to grading coins, so there is a lot of knowledge out there, and you of course want to know everything. You can read books about coin grading, but until you actually sit down and grade coins, and have some experience under your belt, you don’t qualify as a good coin grader.
Now, that you decided to learn how to learn, where do you start? Get a good reference book, a magnifying glass and break out your coins. A magnifying glass is first of all a good source of light, and of course you can look at the intricate details on the coin using it. Take each coin and go observe it thoroughly and grade it with guidelines from your reference book or manual. What are you looking for? Hairline scratches or cracks, dents, abrasions, bag toning, dye errors etc.
You should also make a habit of attending coin shows, where you can see different coin collections and how they have been graded. Coin auctions are also a good place to go because there you see the result of the grading. If you are in good terms with your dealer, ask them to share a few tips on how to grade coins, or to even refer you to a coin grader who could train you as an apprentice. ANA has courses and workshops on coin grading. If you can get into one of them, that would be of great help also. When you are confident enough, then you can venture out and pick coins to specialize in for instance ancient coins, gold sovereigns or Morgan dollars.