In this article Orhan Kavrakoğlu explains the logging levels commonly used in software alongside with some pertinent examples as well as recommendations and best practices such as in which case to use which particular log level and how to present them to the target audience (i.e. other developers, system administrators or DevOps people) so they get noticed in accordance with their respective importance and urgency.
As mentioned here before seemingly trivial improvements such as providing better context in your log messages can make an enormous difference to those using your software.
So, by putting in this effort and picking this particular low-hanging fruit you’ll make your software much more useful to both fellow developers and users alike.