For some 2-3 years, I was ranked on the first page for my moderately competitive keyword, and I DIDN'T GET A SINGLE SALE! I even wrote to the merchant asking him if his affiliate links were working. I even posted on Warrior Forum asking if this darn merchant was stealing from me!
Even after some 2 years+ of not making sales, I looked at my site and thought it was just brilliant. A very impartial review, and to this day, after all I've learned about copywriting, I don't see anything strikingly wrong about my review site.
Now, just a few days ago I started making one sale per day for just 10 visitors per day to my site. I'm ranking #1 for my "moderately" competitive keyword (yeh, and only 10 visitors per day, but such is the competition for Clickbank products).
This came after the merchant changed his salespage. I haven't changed my site since I set it up 3 years ago.
Now the lesson I learned from this is you gotta make sure the merchant's salespage is darn good before you put a lot of effort into promoting his product. I know that everyone tells you this, but you don't really learn properly until you experience it for yourself.
Hah, and all this time despite my own site looking great in my eyes, I always thought it was my site that must have sucked, but it didn't, twas the merchant's salespage to blame.