Step 6: Choosing a DOCTYPE
You start your sentences with a capital letter; start your HTML with a DOCTYPE. It's just basic grammar.
You benefit. Many of the tips in the rest of this series will require you to know what version of HTML you're using, because the instructions will be slightly different. So you need to know what DOCTYPE is currently in use on your pages, or add one if you don't have one.
How to do it
SiteBuilder users don't need to do anything to achieve this; all SiteBuilder pages have a DOCTYPE inserted at the top of them automatically.
The important thing to know for the rest of the series is whether you're using HTML 4 (any variant), XHTML 1.0 (any variant), or XHTML 1.1. You'll see why in step 7.