Whether it's exceeding expectations or offering value in some unique way, you need to make the best impression possible. The last thing people really want is to be just another customer. This is why under-promising and over-delivering is often said to be the best way to provide excellent customer service. It's simply true.
As a writer, I always try and look at an assignment as an opportunity to enrich people's lives in some way. This isn't always easy, of course. Many clients expect people to simply mill through articles and barely reach assigned word counts. Often times, however, I'll be given a topic that I simply cannot write within the specified number of words. I'll often write an extra 100 words or so, which is typically fine in Web writing. That can be a problem in print. But my Web clients always appreciate that I write what I actually can rather than just what I was expected to do.
Of course, it takes more than writing extra words to add value. Over the years, I've made an active effort to reduce fluff in my work. It's a bad habit some article writers get into, especially when trying to write a ton of articles. In the past, that's partly why I can be so picky with taking assignments at times. If I can't find some new or quick and concise way to write about a topic, it's simply hard for me to write. That's a common issue, so it's what I decided to take on as a challenge. Solving challenges like that make you better at your craft. It also makes you a special kind of professional.
You can have the greatest website and the best offers to draw people into doing business with you. But it's going where most others won't go or do the job as well that leaves the best impression. That's what makes you the best kind of pro.