A persuasive text aims to convince the reader/audience of a particular idea or position regarding a specific topic. This means that as a starting point, you should determine the main argument/position that you will adopt in your persuasive piece. Ideally, you should state your central argument at the beginning of your piece.
This brings us to the structure of your persuasive piece. Once you finish introducing the topic and your main position, you can then move on to the body of your piece. This is where you will be able to present and explain your main points in depth, as well as make effective use of relevant techniques (here, the texts that you study would be useful). Importantly, you should also determine the type of arguments that you will be making in your body paragraphs. For instance, you may choose to argue based on logic (rational arguments), or you could present arguments to trigger an emotional response from the reader/audience (emotional argument). You should ensure that this is consistent across the three body paragraphs that you write (which I believe is also the recommended number of body paragraphs). Further, using subsequent body paragraphs to expand on arguments presented can also emphasise consistency, creating a better flow of writing and a higher quality persuasive piece overall.
When the body of your piece is complete, you may include a concluding paragraph to briefly summarise your central argument as well as the main points that you made in your persuasive piece.
I hope this helps!