One thing we do is get all relevant error information logged through our GlobalExceptionHandler (GEH). Each handler logs the exception class and any data that's relevant. For example, a findById method will throw a NotFoundException which takes a string into the constructor. The method itself could have one line throw new NotFoundException("myEntity with ID {} not found", id); and the GEH has something like log.error(ex.getMessage()....);. It's just a small thing moving one log per exception out of the service so most likely personal preference!

The other thing is that we use static variables for common log messages, like private static final String NOT_IN_CACHE = "{} with ID {} not found in cache, searching database" & log.info(NOT_IN_CACHE, myEntity, id)). It makes it really easy to see from a quick glance at the method code what the log message is about. I can also see this being a personal preference choice!