Here are some to consider:
1) Communication... being able to talk tech with your colleagues is one thing.. but being able take the core concepts of what it is you are doing/need to get done and explain it to the most simple of minds, now that will get you places
2) Ability and willingness to learn... goes without saying. Web/software development are one of those careers where you are constantly learning new technologies, new languages, new frameworks... being able to keep learning is essential
3) the ability to leave personal feelings at the door... As bad as this sounds, you are going to want to either grow some thick skin, or again, leave your feelings at the door. Yes, it's ok to feel a certain way about your work, but remember, if someone is critiquing your work, whether it's a design review or a code review, the critique is meant to help you grow as a developer. Do not take it to heart if your colleagues/seniors/managers give you a bit of negative feedback.
4) humility... No one likes an egotistical know-it-all, no matter how good they are at what they do.
5) knowing when to ask for help...
6) resourcefulness... (if your colleagues are busy and cannot help you, can you find the answer elsewhere?)