How to keep a reader engaged
A good text will raise the reader's interest at the very beginning of the story. Usually, this is done by leading the reader to the topic little by little. According to good pedagogical principles, this is done by passing a subject on a generally known subject to more specific issues. This way the reader's knowledge is built and deepened as the article progresses ever further. This writing technique is able to naturally create a reader's experience of learning without him or her realizing that actual learning is happening while the key idea remains in the background.
Keeping the reader's interest depends on many different factors. The narration must be tight. The reader should internalize the most important and most interesting content first, even though the remainder of the material would not be read. However, this does not happen if the text is entertaining and informative from the beginning to the end.
While writing, you have to keep in mind who the text is intended for. The target audience and their preferences to text should always take into account. One of the most important things is that the intrinsic quality of the text (content, logic, text style and grammar etc.) is good. Another key factor is the external quality of the text (font, background, balance and media etc.). This is because the text is often looked at with the eyes first and this leads to a decision to read it.
There is universal principle in writing - text has to be entertaining. Thereafter, it is important that the text proceeds logically but it also have variations in tension. It is also a good idea to provide positive surprises to a reader.
The interesting text contains questions to which the reader gets answers as the text progresses. In the best stories, only a part of the questions will be answered. Partially of the solution will remain on the reader's imagination, leaving the text in a way open and allowing it to continue in the future. These factors are based on many good stories - way open and allowing it to continue in the future.