I've been working on a novel for the past seven months, and actually finished writing it, but I'm in the editing process now and the only thing I'm not sure about is one thing. I know you're supposed to double-space at the end of every sentence, but I'm not sure about after dialogue where the sentence ends in a sentence-ending punctuation. Here's a random example: "I have nothing anymore." He walks away. Would you double-space between the quotation mark and "He"? This has been bugging me for a while now. EDIT: Oh, and I'm also curious as to whether or not I should bother to underline movie, book or TV show titles. I know I can't italicize them, but I'm not sure if underlining is just for word emphasis or if it should be used for media titles as well.
Yes. If you are placing two wpaces after full stops, you would also put two spaces afte the closing quote mark above. However, the two spaces between sentences is a vanishing standard. I doubt many publishers will look down on you if you don't follow the standard, but if you do, do so consistently. If you ever took typing classes, you probably can't help yourself tapping that space bar twice at the end of every sentence anyway. Just an FYI: Double-spacing refers to vertical separation of consecutive manuscript lines, not the doubling of spaces between sentences in the same paragraph.
Underlines in novel manuscripts are often used to indicate words that are to be typeset in italics (like book titles). Some writers like to use both underline and italics (in their manuscripts), while others do use italics, in fact. In print, the underline is not ordinarily used (other than for some unusual emphasis and not typically at all in a novel). Movie titles and TV shows can be shown by just capitalizing the title and/or putting it in quotation marks. Be consistent and know that your publisher will probably have a particular style preference. But first, you need a publisher. What's important for your agent is that it be clear what you're suggesting (i.e., that you know what you're doing) in your novel manuscript.
The standard for manuscripts is that underlining denotes text to be rendered as italics. That is because typewriters can't render italics.