One of my favorite and often used tips in Microsoft Word is the creation of non breaking spaces. Non breaking spaces are spaces that can not be broken at the end of a new line. They are useful when you want to force two separate words to be on the same line. For example, when typing "20 mph" it looks really stupid if the "20" is at the end of one line and the "mph" is at the start of the next line.

To type a non breaking space in Microsoft Word, hold down the option key (on the Mac, may be control on a PC) when you press the space bar. This will force the separate words to always be on the same line.