Remember, a thesis must include your argument! You must make a point and stick to it. No wishy-washy.
Basic structure you can follow:
Introduction: state your thesis and introduce your ideas
Body paragraph: Topic one
explain your ideas, be convincing
Body paragraph: Topic two
explain you ideas, be convincing
Body paragraph: Counterclaim
Some might say..... , but that is not right/correct/valid because...
(remember ethos, pathos, logos, and the fallacies you learned about in English 3)
restate your argument in a way that is convincing and surmises the thoughts presented in your body paragraphs.
Remember! You are trying to convince your reader to agree with you. Do not present both sides of the issue, do not be balanced! Be convincing. When you are talking your mom into letting you do something you don't give her the reasons to tell you no, you only provide her with the reasons to agree with you and then convince her that the reasons to say no are wrong. Do it like that!
Here's a play list of youtube videos that may help writing an argument essay over the break if you need some support.