Some fake autographs are easy to spot especically when there is an obvious physical discrepancy, or some other inconsistency with known facts. In particular, be careful to check the identity and publishing date of the originating article.
For example, since Elvis died on 16th August 1977 you won't find an authentic Elvis Presley signature on any CD or cover/inserts
When testing for machine generated reproductions on photographs, one crude yet effective method is to run your thumb over the signature. If you cannot detect a change in the surface texture of the ink on top of the photograph then its most likely a facsimile. Some more subtle techniques for identifiying autopen signatures are explained elsewhere in this article.