Being familiar with the possibilities is the key to getting the right results every time.
You'll seldom use more than one or two of these tips in the same document. Start by applying the tips in order - proceed down the list, only if needed. Instead, try these simple tips to force overflowing content onto a single page. You've probably spent a lot of time perfecting the formats you use in your Word documents, so changing those to force content to fit on a single page is often counter-productive. Nobody wants a two-page document when one will do, but often that's exactly what you get.