I have been learning syntax for PHP and practicing it. I come from a .NET background so masterpages always made things pretty easy for me when it came to headers and footer
For small sites, include/include_once and require/require_once are great, I haven't built a site without them in years. I would, however, recommend making sure each of your include files is a discrete code block that is valid XML. What I mean is don't open a tag in one include and close it in another, or vice versa - it will make changes complex and more prone to break things because you have dependencies between files. Happy coding!