Choose a profession that you have read about in a novel and found interesting. Read some non-fiction about the same job or profession and compare the view the novels give with the view non-fiction books do.
It is quite likely that you will find that the novels either romanticise the profession or make it seem in some other way different from what is actually the case, depending on the kind of profession and the kind of novel.
This is, for example, common in crime novels. If crime novels are to be believed, private detectives frequently investigate murders, kidnappings, rapes, bank heists and other serious crimes, while in real life you are more likely to find them digging up dirt for divorce cases or running background checks on someone’s potential spouse or employee. And specialised forensic experts like pathologists and physical anthropologists, who in real life are confined in their work to the laboratory and the courtroom, in the books always seem to be questioning or chasing suspects or investigating aspects of crimes that have nothing to do with their training.