i'd say that othello is loved at the start , preferably because he loves himself , he appears very egotistical , when brabantio comes to accuse him of theivary ,othello answers "keep up your bright swords for the dew will rust them" which shows that othello really doesnt think brabantio or the soldiers would harm him because of his stature
and later othello beleives that the Duke loves him so much that his (othellos) service will "out-tongue his complaints" refering to Brabantio
already we kno that Iago "hates the moor" and throughout the play he always refers to othello as the "moor" or "moorship" , which shows his racism and obvious hate toward him ,
the fact that othelllo is black (or of a darker complection) and has a higher postion then he ,Iago, just angers him more.
when othello starts beleiving Desdemona does not love him after hearing Iago's words , he accuses his skin and claims to be "cursed" with it. which exentuates the fact that he beleives hes an outsider
but basically , othellos war history and service in the field is what really impresses the Venetian colony so much , one would ponder how he would have a high position if he were outsider , but then realise it was his war service , and his ability to sweet talk to people with his beautiful imagery and his strength of character .
hope that helps i probably draftted a bit away from the question but you could maybe use some of the ideas in it for your essay