TOP 5 ACCESIBILITY MUST DO'S

Hi all.

I have been working for a web design company for 3 weeks now, but im in need of some HEAVYDUTY ready made and proven principles to include in my workflow.

With accesibility being an important but much overlooked aspect in web design, there must be a core segment of requirements any GOOD designer makes sure are available when coding their websites.

I mainly use CSS and only know the very basic requirements of accesibility code.

What i wanted to gauge from you guys out there who code with accesibility in mind, which "rules of thumb" you MALWAYS make sure you include in you code and the effect (if any) it has in how you structure your code.

I know this is pretty generic in nature, but I need as much help in this area as possible in my job which requires to pass AA standard.

thanx to anyone who can assist me.