Hello
First take a sheet and make an outline with what you want to say, to go well you would have to start with the introduction, continue with the knot and finish with the ending.
Introduction: You explain a little about the topic you want to talk about.
Knot: You explain advantages and disadvantages.
End: You give your opinion of the subject, but do not do it as a small child! “I think … For me … In my opinion …” That does not look good in an argumentative text.
You could try an argumentative text with this topic “private or public transport” or if you prefer “traditional book or computer in class”
Animo in your text!