It really depends on how you’re doing it, but usually you have a theory of some sort and then you find a real life example (text, speech, ad etc.) that is relevant to the theory. Then you see how does the real life example follow the theory you had and how do they differ, as well as why they differ. You should also present the theory and the real life example shortly before analysing.
The important part is to remember to analyse. A student in my class just presented a blog by someone and she didn’t analyse it at all which was a huge mistake since you don’t get any points in criterion B.
Our teacher told us that she will reduce points if you use cue cards or read speaker notes, so I’d avoid doing that.
I got 27/30 in my second FOA on advertising to children although I’m not even that good in English, so FOAs aren’t that difficult + you always have the other opportunity for your second FOA!