Know your learning community
It may be stating the obvious, but every school, every learning community is different. Not only that, but even if you stay in the same school for any period of time, the nature and needs of that learning community will change over time.
To quote myself <grin>,
Before you can create an Information Literate School Community you must be part of that community. 'Classroom refugees' who treat the school library like their own personal palisade are non-starters in this quest. The school community is however a dynamic organization. Staff turnover alone requires you to constantly induct new staff. A constant stream of new students, changes in curriculum, shifts in departmental goalposts: these all demand flexibility, adaptability but above all persistence, patience and a passionate belief in your own role and mission within that community. (Spence, 2005)
Professional Knowledge
Learning and sharing with colleagues is almost an inherent trait for teacher librarians. Our lives are spent collaborating with others and most of us are service oriented. Our professional collegiality is a wonderful thing, as attested by oztlnet and the work of hub groups and professional associations at local, state, national and international level. I have to confess that most of my professional reading these days is via the web, rather than hard copy journals and books - a sign of the times or a sign of lack of time? I have pointed to some important sources and useful links elsewhere on this site.
Initiative and proactivity
Successful school library management is not about keeping the kids quiet and the shelves tidy. We are not custodians or gate-keepers. Most of our work should revolve around making information physically and intellectually accessible to all. Knowing how to catalogue and index resources, how to manage an automated library system is obviously important for the former, but the latter is about working with people - staff, students, parents. Every successful school library has a TL who is 'out there' working with people, someone who has ideas and can convince others to join in enacting them. This can of course mean taking risks and going outside your comfort zone.
People skills and pragmatism
Tact, diplomacy, good listening skills - these are all important but there is no reward in becoming a 'doormat' who works themself into the ground to meet the needs of others. Sometimes the most important word (for your sanity, if not the respect of others) is 'No'. Constant complaining is however counterproductive - don't just whinge, come up with a possible solution to the problem. Even if your solution is rejected your constructive response will earn you more respect than constant complaints. Accept that you will never get everything the way you want it. There will always be 'blockers'; so 'work with the willing'. People need time and space as well as persuasion to change their ways.
Attention to detail and documentation
Keeping the school library - its people, its resources and its services - at the forefront of people's minds is all important. Celebrate your successes, let everyone know what you are doing and how well you are doing it - then even the reluctant will consider joining in the fun. The Principal and other school leaders will always respond well when kept informed.
One example of this documentation strategy is the "team statement" that I have used successfully to fight proposed staffing cuts at more than one school.