The standard rule is this: “show, don’t tell.” Instead of telling your reader that Jane is “sad,” show the reader by describing Jane’s demeanor, her tears, etc. You’re supposed to allow the reader to experience Jane’s sadness with her.
But in a 80,000 word manuscript, chances are you’ll do at least some telling. The temptation to “tell” usually arises when you need to share background information, summarize events, or provide context for what’s happening.