At its core, argumentation is an attempt at persuasion. At this point, you should already be describing the reasons that defined the thesis statement. Devote a small paragraph to each of them and make sure each one is complete, play on their contrasts--try to make sure that each subsequent paragraph is different from the previous one without breaking the logical chain. The main criteria you need to follow in your argument: subject matter, sequence, chronology, and contrast. Avoid one-sentence statements: you must build context for each argument. Remember that the thesis statement can also be given at the end of the paper; don't lock yourself into a strict sequence of highlighted parts.
The main mistakes in argumentation
Repetition. Do not develop the same idea in two paragraphs, it is contrary to their isolation. A new paragraph - a new argument.
Superfluous information. Make sure that any of the sentences relate directly to the main topic. Even if you have an overwhelming desire to write an incredibly interesting fact, reread it several times and think about whether it is better to use it as a "hook"?
Inconsistency. If you use a link to another reason in the next paragraph, make sure that reason has been described above. Don't confuse the logical connection by getting ahead of yourself.
Conclusion
In the last part of the essay, you need to conclude your thought succinctly and concisely. Summarize the reasoning, briefly repeat the thesis, if it was at the beginning of the paper. Or give the thesis statement, if you decided to place it after the arguments.
The main mistakes in the conclusion
New arguments. The conclusion is a summary, not an informative one. Don't add new reasons at the end, better add another paragraph to the main body.
Repetition. There is no need to describe the structure of the written work and literally repeat what is written above - if the reader has reached the conclusion, he has already read it.
Working with sources
If your essay requires large amounts of factual information, you need to work with sources properly. Don't rush to mindlessly copy information from Wikipedia. If you do refer to this resource, only to the references section. It is best to find the information you need in scientific literature and original scientific articles. But even then, be critical of the information, because many books were written tens or hundreds of years ago and may have lost their relevance, and scientific research may have been conducted in order to find confirmation of a theory, rather than to uncover the truth, which makes them lose their impartiality.