http://www.codecademy.com/ is a good suggestion, and look for the Python lessons.
Also look for the older age level tutorials on code.org.
And, you said, “Of course, I tend to fail miserably.” It’s normal for code to not work the first time or even the first many times. That’s called “debugging.” A big part of improving at CS is learning to fail a whole bunch of times but still make things better progressively.
“I have not failed. I’ve just found 10,000 ways that won’t work.” – Thomas Edison