I've done some personal sites and owned a domain for a while. Mostly used as an email server. The website was pretty barebones with just some flavor text saying hello.
In CIS 147 Internet Publishing, you learn how to code your website by hand from scratch. I highly recommend this course.
I've never learned proper use of html and was always a copy paster. Now, I know a lot more. For example, Headers and Paragraphs. I never knew to put text inside paragraphs or to make headers to better align the website in whole.
I will know how to format my websites a lot better than before.
I solved them by going to w3 schools. An excellent database for more than HTML resources.
Khan Academy was the most useful. I can do the work at my own pace and it was very interactive. It helps you when you're wrong as well.