A clear vision is the most important factor in ministers' morale, according to the author of a new book on clergy leadership.

Vision trumps all kinds of external circumstances including heavy workloads, says the director of the Church Pastoral Aid Society (CPAS).

Graham Archer has written Don't Lose Heart, part of the Grove Leadership Series, in response to the findings of research into clergy morale commissioned by CPAS in 2013. The research revealed that 31 per cent of clergy would describe their present morale as 'very low' to 'average'. More than 350 Anglican clergy were surveyed, across more than 30 dioceses.

In the book, Archer draws lessons from 2 Corinthians, in which Paul enumerates the difficulties he faces but insists that he is not overwhelmed by them. He identifies five key factors which can boost morale: spending time with God, setting appropriate boundaries, having supportive relationships, knowing your priorities and seeing the fruit of your work.

He told Christian Today that while the context in which clergy ministered was relevant, with some situations potentially more demanding than others, it did not determine morale. Citing Prof Leslie Francis, he said that "the external context is secondary to the internal state of mind".

Respondents in the survey mentioned loneliness and isolation as factors in low morale, unresolved conflicts in the communities they served and unrealistic expectations. "The current mood within the nation also impacts on morale," he said, instancing the media's concentration on church decline and on reports of internal conflict in the Church of England about issues such as gay marriage.

"The difference is in having a vision for what you're doing," he said, adding that the need to improve training was vital. "When most priests trained, the model was that of one vicar for one parish; then they find themselves the vicar of four, and they haven't worked out a vision of how to lead them.

"You need to have a vision for what you're doing and appropriate levels of support and training.

"The emphasis in this book is not on how terrible things are, but on what we can do to spur each other on and find a more positive way."

Among issues it deals with are the importance of a healthy lifestyle, accountability and mutual support, honesty and prayerfulness.

Rev Will Vanderhart, pastoral chaplain at Holy Trinity Brompton and director of the Mind and Soul mental and emotional health foundation, said that clergy morale was noticeably dependent on the setting in which ministers worked, with comments to Mind and Soul indicating that rural clergy with multiple parishes often struggled.

"I would say that assumptions about the Church of England parish system made centuries ago no longer apply," he told Christian Today. "Many villages in Surrey or Berkshire have very few residents seeking ministry from the local parson. Local people are desperate to keep the church because it adds value to the village – but that's very different from a mission to make Jesus known."

He called for more appropriate training, saying: "I would question the training model that focuses on learning biblical Greek. It needs to offer a social work model of education, dealing with issues like mental health, aspects like reconciliation, arbitration, marriage and vulnerable adults.

"I'm not surprised that some people are overwhelmed and disheartened – they've learned how to translate the New Testament, but not how to make an impact in areas where there is gross social dysfunction."

He too highlighted the negative impact of much media portrayal of the Church, saying: "Father Ted, Rev and the Vicar of Dibley present a picture of the vicar as a bumbling buffoon, overseeing a declining parish. There is a disheartening picture in the media of the minister presiding over the funeral of an institution. Actually, globally the Church has never been bigger nor its future looked brighter."

Don't Lose Heart and other titles in the Grove Leadership Series can be purchased here.