How to improve search suggestions?

Hi everyone. I have a question regarding Sharepoint. 

I have various websites with documents (PP, Word etc.). If a user searches for a document with keywords, the correct document should be displayed in the search suggestions so that the search does not even have to be sent/entered.
However, this is usually not the case. 

Sometimes documents are found, sometimes only after they have been entered and sometimes not at all. I then filled in the names and descriptions in the document library and made sure that the names of the documents and titles matched, it got a little better, but it still doesn't work for some of them. 

How can I get the search suggestions to display the correct documents with just a few keywords?