When I say I'm not marketing myself correctly, it's exactly this point I'm talking about.
At the moment my value add for my clients is my previous experience and my communication skills. I try to reply to emails as fast as I can, that alone sets me apart from most other freelancers.
I would love to be able to sell myself in similar terms to the way patio11 does, but as you rightly state it takes a lot of experience that I for one don't have, yet.
That being said, I've read so much information about on-line conversions techniques, have run successful (profitable) affiliate PPC campaigns, got on the front page of hacker news multiple times and done other things that maybe 99% of other people on the planet have never done.
I'm sure there's something in there that I can sell as a value add.