Help with my thesis on Iago and Jealousy in Othello for an 8-10 page

I have always had the hardest time writing thesis statements. No matter how hard I work on them my teachers always seem to tell me the same thing. That my thesis is weak or not argumentative enough. Now I have an 8-10 page paper on Othello due and my thesis does not seem to be able to spread out over so many pages. Is there anything you would add or change to my thesis to give me more to add to my paper? Thank you.

"By taking advantage of this emotion Iago is able to control most of the people around him to work towards his own selfish desires. Shakespeare uses Iago as a villain in Othello to show the destructive nature of jealousy in human beings."

Maybe you can go deeper with jealousy. There are different sources of jealousy. Othello was jealous because of love. Iago was jealous because of narrow minded. Perhaps you can indicate the different resources of jealousy in your thesis statement so that you can elaborate more later.

Hope this could help:)