Content
Should discuss all the points mentioned in the task notes, i.e. reasons for setting up the club, its organisation, costs and any other points. It could also offer the readers of the proposal the chance to give their feedback.

Range
Language of analysis and recommendation/ evaluation (e.g. 'What about if we ....'/ 'We might want to consider how we ....').
Vocabulary for evaluating costs and providing solutions (e.g. 'if everybody chips in...') as well as terms associated with clubs (e.g. 'members/membership', 'venue', etc.) could be used.

Organisation
The proposal can have a similar format to a report, i.e. divided into clear paragraphs with appropriate headings for each section. The aim or scope of the proposal should be clearly stated early on.

Register
Semi-formal. (Note: Proposals are usually in a formal style but in this case it may alienate the reader.)

Target reader
The departmental colleagues would be informed and would be able to use the proposal as a good basis for setting up the Film club.

Language accuracy
Does not have to be completely accurate but any errors should be minimal.