I have a new rule of thumb for Web development: the 90-50 rule. This rule comes into effect when you get 90% done with a project...and only have 50% left to do.
The details are what kill you, and they trail on forever, it seems. So, when you’re 90% done, remember the 90-50 rule, and know that you’re really only 50% done.
I didn’t make the rule, I’m merely pointing out the obvious.