Does anybody have an idea about how to write a product review leading to a sales page (like e.g. for clickbank products)?
The best way to learn how to write a good product review is to learn from others. You can search the items you want to review, and get enought information you need. In your search, you will find someone wrote for the products or the similar prodcucts. Then you can copy or refer to their writing. I mean you can follow good reviews' structures. Then you fix every parts with the matirials you get. The most important thing you want to show to your customers is the selling points. Just forcus on it. Tell why your customers want to buy it.
A formula alot of people use are adding value to the product review. They start out by writing a headline that claims to tell you if the product is worth it or not. Most of the times it will be but they add a few cons to make it sound like a real review. They then add a bonus that is supposed to relieve the product's weakness and if you purchase under their link you get the bonus. I'm sure you've seen this alot and the reason why is that it simply works.