Great article. I would just add a few more!
A Junior DBA needs to have the ability to follow written instruction while the Intermediate DBA (as well as the Senior DBA) should be able to produce clear documentation and instruction. Many DBAs just "forget" to write down what they did/do (mostly because they haven't allocated their time properly, and some from the mistaken fear of being "replaced" if they reveal all). However, such timely documentation will not only save them time/hassle when it comes to repeating/recreating the same steps when the situation occurs again, it will help them move up by providing a way of clearly delegating work to a junior.
The ability to intelligently framing questions and providing the right details and environments with the questions seems to be sorely lacking nowadays, especially among the younger folks. Whether you are interactiving with MS Support or a great forum like this, you need to able to do this well in order for someone to help you with your problem.
Another personal trait that is necessary for all levels is curiosity combined with caution. Just getting to the bottom of a problem may/will not only reveal the solution, it will also give us an opportunity to learn something more. (Cautionary note - don't try it in Production unless you have tested it elswhere !
Finally, one needs to be teachable. This is again applicable at all levels, but just for the juniors. After 22+ years in IT, I still learn every day and am open to saying that "I don't know" followed by either "can you educate me on this" or "but I can certainly look it up".
Happy new year to all,
Co-Author: Oracle Database 10g Insider Solutions http://www.samspublishing.com/title/0672327910