Who are you writing to?

This is the first and most important question you must answer well to succeed with text. Neither good formulations, an easy and appealing language, nor correct grammar can save a text that misses its target audience.

The 90% rule: we are limitlessly self-centered

No matter the product/service or segmentation; it is a psychological fact that everyone wants more attention and recognition than they (we) receive. We are born this way and raised this way.
The human brain has one main task, to keep its holder alive. Millennia of evolution and technological advancements do not change the species' baseline; we must obtain food without becoming food.
We have senses that alert us to sudden movements, taste/smell, and hot/cold/sharp. And we always have spare brain capacity to interpret and react instantly when we must. Being focused on ourselves is nothing to be ashamed of, it is a biological - quite obvious - necessity.
As children, we are cheered on by parents for every step we take on the long stairway to independence. The first words, drawings, and little things we manage on our own trigger a stream of positive feedback and love. Has drunk up their milk, has tidied up themselves, put on shoes, tied laces, remembered to say thank you, got sound out of the recorder, and so on.

Innate self-centeredness combined with an upbringing bathed in attention, what happened?

Kindergarten, school, recreational activities, the military. Through social training (reward/punishment), you experience that you are one in the crowd. Raise your hand, wait your turn, conform, do as others say. In the classroom, you encounter a painful meeting with the flock's internal justice, peers' (and unconscious
teachers/activity leaders') ranking. Some are stronger, faster, more beautiful/handsome, and more skilled than you. More popular. You learn to live with not getting as much attention as you wish.
Through trial and error, you experience that it is socially accepted and expected that you should listen to others, not talk about yourself, and that showing care, consideration, and interest in others yields various forms of reward.
Over 10-15 formative years, you have gone from being an attention-demanding youngster to becoming one of the adults, one who follows social norms and behaves. Wrong!

The truth is that you are just as self-centered, but society around you has trained you not to show it. Deep down, you are still that little child, always seeking attention and recognition.
You have, to put it mathematically, 90% of your attention on yourself and the remaining ten directed outward at family, friends, news, and the rest of the world - there you have the 90% rule.
Texts that sell have in common that they aim where it is easiest to hit, within the 90% rule. They talk about something that feels relevant because it is about the recipient, not about you as the sender.

Initially, I simplified the first, most important question so that the answer was general.

Who are you writing to, and what do you know about them?

We are quite different to be so alike. Here, common demographic data such as age, gender, residence, family type, education, and income play an important role. The same goes for psychographic ones such as politics, religion, taste, interests, and cultural capital. What do you know about them, or what can you find out?

All this is about something as simple as tailoring the message, something you actually know from before. When you talk to a child you use a lighter voice and simpler words. You also know how to first get attention, then sell the message.

(heading) Would you like to go to the Water Park?

(body text) There are just a couple of things you and mom/dad have to do first: We need to finish our meal and tidy up a bit in the hallway and your room. As soon as we're done, we're off to the Water Park.

Here you know the target group, talk about something that is attractive, and tell what the target group must do to get it.

The recipe for creating advertisements/texts that hit the mark and sell is to talk about something attractive and tell what the target group must do to get it.

It is years of socialization and the desire to act professionally and maturely that make you experience that it is difficult to write good texts at work. It seems much safer - also in terms of getting internal acceptance - to write about the company's size, history, sustainability, and innovation. It also seems safer to create an updated version of the old text, maybe also use the same picture as last time or one that is similar.

It will likely get the boss's stamp of approval quite quickly. This way, efficient you gets the job done and you can move on to the next task.

It seems safe, but you miss the target audience and lose the sale.
It does not work.