Area of Focus Comments
Coin buyers tend to undergrade. Coin sellers tend to overgrade. These facts reflect human nature. Make sure you learn to deal with them when grading coins. Whatever coin you are grading, pretend you have no interest in buying or selling it. Be objective as you determine the coin's grade. Actually, practicing objectivity when grading coins is easy to do once you get the feel for it. Remove biases. Practice fairness.
Some think that by learning how to grade a dozen or so coins, one suddenly becomes an expert grader. Wrong. To be a good grader one has to be able to grade coins reasonably, accurately and on a consistent basis. Ever try to grade a coin that you've graded before (and forgotten the grade so it's like grading a fresh coin) and compared your answers? Consistency is when you can get the same results eight or nine times out of 10 on a regular basis. To be able to do this you have to have an established technique and you have to practice, practice and practice. Accurate and consistent graders stay in "shape" by grading thousands of coins per year.
Some think that coins in general automatically have grades that magically fit the exact definitions of EF-45, AU-50 and so on. Wrong. Coin can be EF-45+ or 45++ or 50- and so on. But we don't use numbers like 46, 47, 48, or 49. That would suggest the grading process to have a precision way beyond reality and our ability to be consistent. Some coins are "no-brainer" EF-45's. They're easy to grade, easy to be consistent on and also easy to get general agreement from graders with moderate experience. Borderline grades (like 45+ or 50-) are confusing because on one day you may choose one and another day be convinced it's the other. This happens to very experienced graders as well so don't assume you are doing something wrong. In cases like this adopt a conservative approach. choose the lower one.
This may sound a little simple but to properly grade a coin you have to look at it. The higher the grade, the more careful the search for hard-to-see marks and so on. What's the point in declaring a grade if you haven't thoroughly gathered all the data that affects a coin's grade. It makes sense when you think about it but most people who are having trouble grading coins are poor at this basic data gathering stage. For best results always try to grade under standard (i.e. yours) conditions. The lighting, background noise and time are all factors.