Instructions
Learn the language of the grading system. American coins are graded using a point system that ranges from zero to 70. Zero is the score for an extremely mutilated coin, known as the basal state, and 70 goes to a perfect, uncirculated coin. The Silver Coins website has detailed explanations of the differences in silver-currency grades.
Study photographs of different coin grades. Learn to recognize the subtle visual differences that change a coin from being graded "extremely fine" to "very fine," or "good" to "very good." Look at a bookstore or library for guidebooks that will illustrate these differences, such as "Grading Coins by Photographs," by Q. David Bowers and "Making The Grade: A Grading Guide to the Top 50 Most Widely Collected US Coins," by Beth Deisher.
Learn the specific problems in grading Franklin half dollars. It is important to know the idiosyncrasies of these coins, which include a tendency to show contact marks and often have a poor quality of strike. Find books that focus specifically on Franklin halves and discuss their particular problems regarding establishing grade. Some guidebooks on the Franklin half dollar are "The Complete Guide to Franklin Half Dollars," by Rick Tomaska and "The Franklin Half Dollar: Collector/Investor Guide," by Lyman L. Allen.
Consult a coin-grading service. A coin-grading expert will give a professional evaluation of the grade of a Franklin half dollar. There are many sources for this service, including the Numismatic Guaranty Corporation of America and the Professional Coin Grading Service. Each service has different fees.