This is not just a personal responsibility – how your job is defined, internal and external expectations, organisational structures are some other areas which ought to be looked at. But it can be a very personal thing, with your own motivation and personality type making a huge difference.
BurnoutBusters is part of FriedSocialWorker.com (we love the name). American, so while the differences in issues wont be that great, the availability of further resources (e.g. books) may be.
International Stress Management Association UK is more for the personnel professional, and exists to promote sound knowledge and best practice in the prevention and reduction of human stress.
Managing your manager (and colleagues)
Where you report to a management committee, particular trustee or such, take a look at the Governance page. There may well be issues around responsibility and power in the organisation.
Managing upwards is a skill in itself. It can be tricky getting across to your boss why something is important, especially if it falls outside their immediate remit or experience. They are likely to have their own pressures and priorities which they can’t relate to your concerns, so you have to help them. Certainly most in the voluntary sector have, or did have, some commitment to the cause, which can be an advantage in finding a way of communicating (by connecting on an area of mutual interest for instance). However, there are also downsides in that individuals can care passionately about a particular aspect or have come to the organisation with their own agenda. If you disagree, relations can become very tense.