Customers, customers, customers...

Overdelivering on a project is the best thing you can do for your customer - and therefore for yourself! An astounded customer is an unbeatable advertisement for your business.
Not only that your customers feel that they got the service as it was described, they feel as if they got more! Perhaps if you look at the monetary value, they did indeed get more.. But they will certainly pay your business each and every cent of that difference.

Customer that is blown away by your delivery will instantly become a returning buyer and a personal affiliate partner. He will recommend your service to anyone he knows, and the best fact about it is - he will speak with pure enthusiasm and joy.
This is a lesson I quickly realized while working as a freelancer on Fiverr.
People will repay you multifold for the work you overdeliver. They will continually come back for any sequential project they require. They will refer you to their friends with similar interests. They will leave reviews that you couldn't even conjure up yourself.

And then comes even more magic.

Based on those very reviews, more intrigued customers will come. Overdeliver on their projects too, and.. Well, it's obvious. A massive snowball effect occurs.

I do Fiverr gigs just for fun. It is a way for me to practice people skills and effective communication with customers. Perhaps a month or two after I started overdelivering, the group of my dedicated customers exploded and I even had to put my account on vacation mode for a while due to too many requests I was getting on daily basis (remember, it was supposed to be a side job for fun, along with my Computer Science projects and faculty requirements, I couldn't let it become a full-time job).

This taught me an extremely valuable lesson I apply in everything I do nowdays.
I used the same technique to land a software engineering internship this summer. I gave my 110% to the task that was supposed to be just an overview of my current knowledge.

I gave it my all. And they recognized it. And they loved it!

The best thing is the positivity that this brings. And the fact that you can use it anywhere and anytime.
Overdeliver on a freelance job, overdeliver on your tasks at work, overdeliver when preparing a meal for someone..

Do it anywhere you go and you will create an atmosphere of delight around you at all times.