The breast feathers and hair above the ear are the highest points of a Morgan Dollar's design, and the first affected by wear or poor die state. More often than not, the hair above the ear will is not well defined on a Morgan obverse. To help determine a weak strike from wear, look for the hair above the ear to have a 'squashed'-like appearance, and maybe some toning. If it's worn, the surface of this area will be missing a small layer of the metal, be flat and might have 'circulation' toning. While most hairlines above the ear will be flat, there can't be any break in luster. The coin must look uniform in luster.
The rest must be left up to the reader, as no grading guide can teach a collector how to properly grade every coin consistently. In example, a coin might look MS65 according to this guide, but further examination by a dealer or grading service, proves the coin has been dipped. Now you have a coin with MS65 details, and most top tier grading companies will not assign it a grade. As stated earlier on, only experience will allow careful discernment of all the little nuances involved in properly grading the Morgan Silver Dollar.
Almost Uncirculated (AU50)
Almost Uncirculated (AU53)
Almost Uncirculated (AU55)
Deep Mirror Prooflike (DMPL64)
Altered Morgan Dollar Examples
Disclaimer: This is just a guide to give you an idea of what your coin might grade. Often coins will grade higher on one side vs. the other. In example, it's possible for a coin to grade G4 on its obverse, but grade VG8 on its reverse. Also, this guide is not a claim that one's coin will obtain any grade listed if submitted to a third party grading service.
Almost Uncirculated (AU58)