There are four main types of SEO-texts. In order to write a good SEO article, we need to discuss all of them one by one:

Marketing SEO texts
The most complex kind of copywriting. That "content", which is mostly offered on exchanges, giving out for selling texts, in fact does not refer to this group at all. The main differences of good selling SEO-texts are as follows:
Not an article for keys, but keys for an article. The selling texts you can hardly find passages like "we suggest you buy wholesale mittens Surgut inexpensively at a discount." Any SEO-selling article must be natural from the beginning to the end. The keys fit into it very carefully, and not breaking the quality of the material. It's better not to insert a query, than insert it awkwardly. This rule works when writing all the texts for promotion, but for selling SEO content this is aspect is especially important.
Use only the semantic uniqueness. The selling text is like a patterned weaving, thinking over each word. No professional author will undertake to break his text in order to achieve high technical uniqueness. I never checked my texts with programs in my life and I will not do it. This is not necessary: if the text is strong enough, it will reach the TOP without any doubts. To be more precise, users will bring it to the TOP giving the material high social signals and reviews.
Easy style and clear structure. Selling texts can only be successful when read in one breath. All these long sentences, complex words, etc. come from evil.
Problem and its solution. The text should clearly outline the problem and suggest a correct solution. When the material has got nothing but cries like "ahh, we are the best", this is not a selling text.

Expert SEO texts
The text that you are reading right now refers specifically to the expert type. Before I started writing it, I collected more than 20 inquiries regarding the aspect on writing SEO articles. However, we'll discuss the collection of keys (queries) in more detail in the next section.
Expert SEO texts are ideal option as a filler for companies blogs or guest notes. You can get excellent targeted traffic using them, however, you have to work hard to achieve a result.
I will explain providing an example. One of the key requests of this article is "how to write SEO-text", as well as its numerous derivatives. By itself, this request is not very necessary to me, since my main goal is to find direct clients, while teaching is my secondary target. It may seem that keys like "copywriter services" would be more interesting to me. In fact, you can be wrong about this.
Sooner or later there will be people who either want to order SEO-texts, or decide to check already available optimized materials on their website. In search of truth, some will necessarily enter the query "how to write SEO-texts." The result is that they will get onto my website.
The rest is a matter of technology: people will decide that since I am an expert, it is entirely reasonable to entrust the work to an expert. This will result in receiving the target customer.
The same principle will work in your case. Are you engaged in life insurance? Then write expert articles about insurance. Do you grow seedlings? Tell people how to do it right. As a result, some of the visitors will definitely become your customers. I hope you understand the principle.
If you write an expert article, make sure that it really helps people. Alas, too often I see nonsense on the websites like "How can I paint the garage myself in an hour? This question is asked by many. To paint the garage in an hour is very difficult. It is better to hire masters. Looking for a master? Make a call... "You feel that you were deceived? This is called manipulation, and nothing but irritation comes into your mind.
You can even put forward your own theses (you know your business best), and the copywriter will write the correct SEO text with keys and good structure on the basis of your theses.
The main thing is to remember the golden truth:
Any good SEO text should clearly answer the questions that are voiced out in the keys. Use the query "the basis of SEO-copywriting". Use the query "the price for the closet" means that the first page should provide you with give the prices. That’s the way it works.

Information SEO texts
For example, you write an article on the request "Saratov Furniture Company". Expertise is not needed here so much, since there is not even a hint in the query itself. Suffice it to say that such a company exists, that it can help, that it has considerable experience, etc.
As a rule, information SEO articles are posted onto blogs or as texts for sections. Examples when article is published on a blog: "the best beds for children," "types of excavators." As for the sections the examples may be: "lawyer in Moscow", "takeaway food" and so on.
As in the case of expert materials, the information article should respond to a request made by a guest. Inserting the massive stupid texts here and there is a sign of dilettantism and a guarantee of losing the position of the website due to low behavioral factors.

Pointless SEO texts
It was okay to write SEO-articles with rubbish content 5 years ago, since people were still coming to such websites. Articles about nothing are purely a stock exchange. There are still hundreds of authors who write basing upon the principle "I sing what I know”. Is this a real study of the topic?!
Texts about nothing with keys that are no longer interesting to people. Such articles wouldn’t be taken even for free; they will do more harm than help. Just a cheap solution for those who don’t care about the website.