1. Soft skills. Getting along with people is probably your most valuable asset. Show concern about issues that people talk about when it comes to the equipment you support. You don't want people saying "He's a great technician, but he doesn't get along with anybody"; nobody will want to be around you if that happens.
2. The truth. Always be up front with the customer about problems or issues, but also come up with the solutions to those problems as well...if you don't know, find out, but don't lie!!
3. Be open to learning new things and applying it right away. The knowledge got you the job is probably useless; how you learn and apply new knowledge will get you farther.