Editor vs. Published version of a title

To add on to what Ben said, it's always a good idea to use the Preview In Browser option for each page when you're authoring, so you can see how things will really lay out on the page when you publish it. Sometimes you even have to make stuff look "wrong" in the authoring mode to make it lay out right in the browser (like if you're putting text form fields into sentences for fill-in-the-blank places in the middle of the sentences).

Keep in mind that Preview In Browser only "pubishes" that one page, so you can't use it to test links to other pages and stuff like that. For that kind of testing, you'll need to actually publish the course to HTML. However, doing that isn't a big deal, and you can do it as often as you need to while you're authoring (it just takes a bit longer than looking at a single page using Preview In Browser and it will force you to clean up any "fatal" problems in your course before it will complete).