What can I do as a designer?
Just to clarify: Making a page accessible to everyone is not a one-man task. Designers have to think about things. Developers have to take action. Product people have to factor in accessibility. And even your customer (if you’re creating a page for a third party) has to be involved in the whole "Let's make our page more accessible" process.
On the following pages you’ll gain some insights into what you, as a designer, have to think about when designing a page. Remember: This is just a 101, an introduction to accessibility if you will.