Best strategy to deploy HTML5

Using 2.4.4

Basically, I want to upgrade my whole site so that it has the option to view everything in an HTML5 environment. Some students use Apple devices and can't view Flash content.

So, from this point on, I want to make my pages viewable on legacy as well as HTML5 platforms.

What advice would you give, and what are the best strategies to make this happen?

Thank you.