Any word processor can produce a dash. However you produce it, don't put spaces on either side of the dash. Dashes often come in pairs. If you want to signal an interruption in a grammatical structure with a dash, you've got to keep track of the grammatical structure, and signal the return to the main structure with a second dash. Somewhat like colons, dashes are flexible enough to let you play with word order to create interesting sentences.
Punctuation follows parentheses without a space.
Question marks and exclamation marks Many students are reluctant to use question marks, but these are common and proper in academic writing. It would be nice to think that nothing would influence a scientist's search for the objective facts. Reality often says otherwise. . . . If you're reporting the end of a world war, feel free to use an exclamation mark. Otherwise, resist the temptation.