How Does Iago Attempt to Poison Othello Against Desdemona and Cassio and to What Extent Is Iago's Plan Working

How does Iago attempt to poison Othello against Desdemona and Cassio and to what extent is iagos plan working
Othello is a character whom from the start of the play does not see any faults within or within Desdemona’s and his marriage. However iago who is without doubt one of Shakespeare’s greatest antagonists but the question remains what motivates iago to betray Othello. Iago believes that Othello had an affair with his wife this or as iago puts it the ‘lusty Moor hath leap'd into my seat' in a way he acts out of insecurity within his own marriage or it could be because of iagos jealousy or the newly ignited rage he found when cassio was promoted to a point where iago himself believes he should of achieved himself.   In the beginning of the pay iago says a key quote; iago says ‘I am not what I am’ in act three and throughout the play the audience can easily see the widening   cavity between who iago really is and what he pretends to be in order to achieve his own goals. We the audience all see what is happening during the play but the characters are all blind to Iagos treachery.
Iago attempts to gain his revenge against Othello in a multitude of ways however in scene 3 one can really see iagos plot of requite evolve as one can really see him begin to attempt to poison Othello mind in order to drive him insane. Iago seems to be extremely skilled in the fact that he anticipates and manipulates characters so skilfully that they seem to be acting normally when in fact they are simply iagos marionettes in his puppet show.
Firstly iago uses his skill of carefully selected narration to build Othello’s trust in him as he seems to be attempting to reinforce their previous friendship. It seems almost coincidental that all these events happen in the play at moments of seemingly scandalous moments shared between cassio and Othello's wife Desdemona just as iago whispers into Othello's ear ‘pestilence’, with the build-up of trust between Othello and Iago built from the...