Need help to write an Essay on Hamlet : What deliberate attempts are made at deception

Hamlet is a play in which nothing can be taken at face value: appearances are frequently deceptive, and many characters engage in play-acting, spying and pretense.  What deliberate attempts are made at deception?  Are the intended audiences deceived?  While some deceptions are perpetrated in order to conceal secrets, others aim to uncover hidden truths.  Which are which?  To what extent are they successful?  Note references to appearances, disguises, pretense, seeming, masks, acting, etc. Discuss the importance of deception in the play.