A development shop can be broadly associated with service delivery (consultation and service at cost) or product delivery (product sold at cost).  I think the following principles could be applied to both:

• Always try to Innovate
• There are different ways of solving a problem. Try finding the best approach.
• Have faith in your teams capability to deliver anything.
• Have faith in yourself and believe that you have potential to change the world.
• You need to have flexibility and the capability to move fast.
• Always try to work in the team but also hold your identity.
• Believe in sharing knowledge and tips.
• Trust your colleagues.
• Avoid bureaucracy and politics like plague.
• Customer is the king. If a customer doesn’t know something be ready with a training session.
• An absurd idea is not always a stupid idea. Be open and receptive.

The core belief is the willingness to innovate and allow customer to be the final judge.