Improving over several iterations of mznlab.net is how I got back on the web administration/design horse after so many years (and writing HTML on notepad).
This is one of those things in which you just have to immerse yourself and persevere. Some things will annoy the hell out of you, but the challenge (and reward!) is finding a cleaner and more elegant approach at every turn.
My advice: exploring the resources below, start with Codecademy's HTML & CSS course, then move to Bootstrap (responsive design is amazing) and finally Django (Python web framework? Yes, please!). You'll likely have to learn a few things about Apache too, if applicable, like how to use .htaccess to only serve pages over TLS.
Finally, StackOverflow is your friend in every occasion: be it Django, HTML, CSS or even Bootstrap.