We are doing Othello as a text, in particular analysing Iago as the archetype of the villian. In terms of how he manipulates others, i would mention:
a) The way he exploits the weaknesses (and strengths) of his victims. E.g. In Othello, He perceives "his free and open nature", andd manipluates it to his own advantage.
b) Another thing I find intriguing about his maniplative prowess is he actually doesn't have to do much (other than dropping a hankachief), and yet, he causes so much destruction. He is able to provoke a virtual metamorphoisis within Othello- transforming him from a blissful newlywed to murder in three days.
c) He also manipulates all the characters you mentioned through his "honest" public persona, and this facade fools all- including his own wife.
d) Look at language techinques too, as these are yet another source of Iago's manipulative power.