HTML cookbook

I don't know what half these meta tags in the boilerplate actually do, so I just copy-paste one and hope it works.

My icon buttons look obvious to me, but I have no idea what a screen reader says when it lands on one.

My page looks fine in the browser, so I don't know if the markup underneath is actually broken.

Every section of my page is a div with a class name, and I can't tell where the header ends and the content starts.

Every time someone leaves a required field blank on my signup form, it just submits anyway.

I have a spreadsheet of numbers to put on the page, but a plain HTML table just reads as a wall of numbers to anyone using a screen reader.

I shared my new page's link in a group chat and it showed up as a bare blue link with no image or preview.

I inherited a page full of center tags and blinking marquee text, and I don't know what's safe to remove.