Create a link to a video rather than embedding it on the web page. Embedded Youtube videos are not as accessible.
When you name a file, make sure that the file's name clearly explains what this file is. Don't name files something like "form.pdf". Say "Student_Application_Form.pdf" instead
In general, PDF's aren't very accessible. Add content from PDFs, Powerpoints and other documents directly to the page; embedded docs cannot be read by screen-readers.
When you name your links, give it a descriptive name. Don't write "click here", "more" or "continue". If a blind person were using the website, they aren't sure what they're clicking on! Instead, say something descriptive like "Click here for the School Newsletter" or even just "School Newsletter".
Don't use pictures of Flyers by itself! Visually impaired users can't read your flyer. Pair a Flyer with plain text, underneath it to explain the information on the flyer.
Watch the use of all CAPS text. It's confusing for visually impaired users!