How do you designate titles (of novels, newspaper articles, etc.) in text? (with examples from Stargate SG-1 and Harry Potter)
When naming specific titles in the text of a story, it's best to use the academic styles. But, there's also a stylistic component.
The standard way of formatting the title of a book, whether it's a novel or a textbook, is to italicize it. Newspapers fit under this category.
"Sam, can you hand me that copy of Chinese Characters: A Genealogy and Dictionary?" Daniel asked, not looking up from the tablet he was translating.
Hermione was already in the Great Hall when Harry walked in, eating breakfast and reading a copy of The Daily Prophet propped up against a jug of juice.
[It is a common misconception that underlining and italics are interchangeable. Underlining was originally used in hand-written documents to indicate to the typesetter when italics should be used. Now, underlining should be used when italics are not available, like a hand-written document. If italics are available, use them.]
Shorter works, like newspaper articles and songs, are indicated by quotation marks.
Schönberg's "Ode to Napoleon Bonaparte for Voice, Piano and String Quartet" came on the radio, and Jack turned it off in disgust.
Harry didn't know it, but Ron had a copy of "Flying Ford Anglia Mystifies Muggles" pinned to the inside of the lid of his trunk.
However, it's important to take into account whether the book/article/song/etc. would be referred to by its specific title. In conversation, it can be more useful to refer to a book or article by topic rather than by title. In such cases, you don't have to italicize anything, because you're not mentioning the specific title.
"What're you reading?" Jack asked without preamble, walking into Daniel's office.
"An article about a new discovery of Bronze Age artifacts in a dig site in--"
"Aht!" Jack interrupted. "Pleasure reading?"
It's also common that someone might know the musician, but not the name of the song.
Sam was tucked underneath her bike when Daniel pulled up to the house, some Ani DiFranco song playing on the radio next to her toolbox. "I didn't know you liked angry feminist music," Daniel called as he got out of the car.
For specific formats not listed here, you can check academic sites or resources. And think about how people speak first, especially when writing dialogue--how often do the people you know refer to a newspaper article by its full name, or even the book they're reading? Think it through from that angle first, and you'll be good to go.
For other articles about quotation marks or italics, check out When is it appropriate to use single quotation marks?, How are italics used in text?, and Grammar 101: Punctuation (Part 3).