
For example, if they see one day a number of backlinks to a website and the next day they see a double number of backlinks to the same website and the new backlinks are to the same page from a limited number of websites in similar ways that may seem strange. They may think you paid for those links. When people see your website and when they write about it their patterns are not similar, they write in their very own way and the number of websites sending backlinks to your website can be much higher. And they will probably send backlinks to different pages on your website with different texts attached to their backlinks so you better write better and more often on your website. You can add a blog on your website so you can attract more and more people on it - those people will write about it if they like it and they will add backlinks for free for your website.
The conclusion is you should be natural. More natural you are more succes you will have. Convince people to write about you instead paying them and you'll be better.