alt text head-desk (hey, that almost rhymes)!

arg. I'm trying, to make my blog more accessible to the visually impaired, to insert alt texts into my url (Which can be read by automatic screenreaders when pictures cannot). According to every instruction that I've read online, the code should follow this format:

< a href="URL.Addressh.ere" alt="text" > Blue Clicky Words </ a>

... except without the spaces.

I try that, and hover my cursor over the link; the Link works fine, but I can never get the alt text to appear. What am I doing wrong?