Too Late for a Green Thumb?

I love gardening, I really do; it's just that, well, gardens don't love me back. In fact, when I am around they'd rather just shrivel up and die, no matter how hard I try to nourish them. Potted plants are like goldfish for me: they look pretty for a day or two, but then they are dead....and some people claim they can

keep theirs alive for decades. What am I doing wrong here?? No clue. BUT I will persist. My newest venture is herbs. I found this article on a blog (See link here) about growing your own herbs. I want to try it. Now that we are moved into our new apartment, I've been casting a scheming eye of the somewhat barren patio. I think some fresh herbs would liven up both the patio and my cooking! (Not to mention saving me some grocery money!)
I have some errands to run tomorrow; I think I'll stop by WalMart's garden section and see what they have-- you know, just to look....
I wonder if it is too late in the summer for herbs though.
      I know nothing.