How to Make Your Web Startup Successful
It’s a little old now, but boy is this a great set of tips for any web startup or web entrepreneur - 10 Rules for Web Startups.
The article is by Evan Williams who co-founded Pyra Labs - the people behind Blogger. He’s now the CEO of Odeo - a podcasting-related startup. He admits he’s made some mistakes along the way, but in my opinion his 10 Rules are gold.
The best part about the 10 Rules is that point number 1 truly is the best point in my opinion - Be Narrow. If translated into SEO/SEM talk - Pick a Niche.
There is a great side-effect if you pick something relatively narrow to focus on - chances are you’ll be able to do what you set out to achieve. If you attempt something too large at the start, you might find it takes so long to reach those goals that you lose motivation and give up.
If you aim to develop something smaller, you’ll find it comes about with relative ease, and then you get excited about expanding and developing your product. There’s a reason it’s called web development.. 
It’s like they say - Release early, release often. Or for a twist - Release something, improve on it.