When choosing a biography subject the choice should be made with a clear head. The writer should choose their subject as if choosing a soul mate to marry.
Some writers know that they would like to write a biography but have no-one in particular they plan to write about. So where is the best place to start to decide who would be a good subject?
The entry into a biography should be treated like the entry into a marriage.
When writing about a person the author will need to honour their promise that the person's life will be documented accurately and love at least some of the process as they do this. This can be difficult if the subject of the biography is an often demonized figure such as a murderer.
The way to deal with this is to realise the difference between loving the person and loving the quest for knowledge.
It can also help the writing process if the author can find some compassion or empathy for the character by first reading about who the person was as a young child.
The health of the writer should be considered when choosing a subject. If a writer is suffering from ill health they have to consider how much energy they can commit to the book and let that influence who they write about.
The life of a long dead English king will require a lot more research than the life of a young and current pop star.
A writer needs to be honest in their intentions. If the aim is to document an interesting life whilst keeping artistic integrity then the starving writer may remain a starving writer. If the aim is to earn money then the writer may need to choose a more popular or contentious figure.
Alternatively the writer could check out the curriculum of local college or university courses and see who they study. A book on one of the lesser documented figures covered in a popular course could be a big success.
The writer should remember this vow on two levels. The first is the actual death of the subject. If they are already dead then the book needs to cover their life all the way to their death even if their later years were less than interesting.
The second death is a metaphorical one. A biography can be a long and drawn out project and the writer needs to keep a sense of momentum to the very end. This is a commitment entered into for the long run.
Before a writer begins the long process of researching a person, a brief check as to whether there would be any legal objections should be done. For most historical figures there will not be any problems but for the majority of people who are still alive it is worth checking out whether there is any legislation, copyright or previous civil law suit which would prevent a writer publishing a biography about them.