How many things have you tested lately? How much time do you devote to testing?
There are so many things that we are able to test online. We can:
If you wonder how the super successful online become successful, a lot of it has to do with testing. Especially in the arena of Niche Websites and Search Marketing. You find success through massive efforts in the areas of testing I've listed above.
Are you testing or just throwing stuff up in hopes it will succeed the way it is? Do you give things only a little while to succeed on it's own then giving up? Or are you giving it time and finding ways to improve on your results?
For those of you that have or can only say you've tested a handful things in any of those categories, I have news to deliver. If you've been wondering why you haven't been successful, it probably has a lot to do with the fact that you haven't been testing enough.
The idea behind testing is simply to test what you think will work, by it's potential or criteria... you keep what did work and throw out what didn't. It's not testing only a little bit or a few things. It's testing until you've exhausted all possibilities and have found the best combination - or can say with confidence such and such a thing isn't working.
Testing is your best friend.
I don't care if your affiliate marketer. I don't care if you're a merchant. It doesn't matter if it's a sales page or a content site.
Everything requires testing.
It's not always about dumping more and more traffic into a project or more link building.. it's about fine tuning the quality of that traffic and making the most of it through testing! It's about improving your conversion rates and results through testing those things I've listed above.
Test, test, test!!!
Got it?? Good. 
-- Matt Levenhagen
Tracking and Analytics - Testing