I've been using PHP Frameworks for so long that I've actually forgot the "best practices" for create websites without one.

Usually I will use Symfony, or more recently I've been using Laravel. A client wants a very simple website, but with certain parts of it dynamic. Due to the nature of the site using Wordpress, or a Framework, is out of the question.

I'm a sucker for priding myself on my code, but I feel like I'm asking such a basic question that it's killing me to ask. But, what are the best practices for creating websites without a Framework?

I like to live by the K.I.S.S (Keep It Simple Stupid!) method of thinking. So, my idea was to just create the .php pages that are required, do any page processing or database interaction on that page, then have the HTML below the closing PHP tag. I would have any helpers/functions in a functions.php file. This is what I remember doing way before I was using Frameworks, and to me it seems like a very old school way of doing things.

I've not created a site without a Framework for literally 2+ years, so I've lost my way with the basics.

Any advice would be greatly appreciated.