Riddles ask that you solve a seemingly impossible situation created through semantics, the willful manipulation of your preconceptions or both. You can best solve riddles by asking as many simple questions as possible and thinking in lateral, unusual ways.
Consider the riddle carefully and have it repeated. If in writing, keep a copy to look at. Begin by asking basic questions about the terms in the riddle, especially "who," "what," "where," "when," "why" and "how."
Do not assume or presume anything. For example, "death" does not always mean "murder," and in speech "ajar" sounds identical to "a jar."
Continue to ask questions and form theories. Speculate about intention, cause and how the scenario ended up the way that it did.
Consider these theories until one fits correctly.