1. Hamlet is of noble birth.
2. Hamlet is the "most immediate to the throne."
3. Hamlet does not have any siblings.
4. Hamlet speaks to ghosts.
5. Hamlet is not, we should believe, of the character to use poison to accomplish revenge.
6. Laertes is "rash and bold, crashing his way into Elsinore. Laertes is not, however, an admirable character; he actively conspires with Claudius to determine the outcome of his duel with Hamlet." source