A creative briefing should be a complete, useful, detailed and well-explained material that will allow us to make a faithful idea of what the client expects from us. It is the orderly, strategic and creative selection of the data that will allow you to define the objectives. In addition to informational, the briefing should be inspiring: not only explain, also suggest.
Clients, this is not a briefing
A call is not a briefing, an email or a couple of IM messages are not a briefing. Please, it is not necessary to do something "formal", looking at essential items such as project background, brand environment, insights & references, objectives, strategy, target audience, desired deliverables, timing... It's the only way we can get a professional product delivered.
Creative, be proactive!
Although these previous considerations would apply to the Clients, we should not leave aside what is related to the Creatives: Waiting for a perfect document that makes us 100% clear seems a dangerous utopia. We all know fellow professionals who act radically, strictly, who "block" the project if they do not have all the structured and detailed information in a specific way. These people consider that closing and waiting for the perfect documentation will make everything work better. Let's be proactive, the ultimate goal is to develop a project "with" the Client, not "against" him.
Is there a midpoint? The collaborative briefing
Not always the people in charge of sending a briefing are accustomed to working with this type of documents or requests, may not have the time or the resources to collect all the necessary information at this point or, sometimes, this quote of Steve Jobs fits: "the customer does not know what he wants, until it is shown". We can contribute from our experience to improve or refine the communication of their needs.
What we really want is to be able to make a proper proposal, so, we have to speak to the Client: request more information, comment on options, propose ideas, resolve doubts, etc. to end this process by having the most accurate idea of what the Client expects from us. It is not a "free consultancy" as some may say, it is a key step to get the whole picture, be able to understand what we are going to do and also draw red lines.
In the past we have made proposals and budgets based on poorly detailed briefings and the results were never "the best", neither for the Client nor for our quality standards. Going through this process involves an additional effort and a time investment on our side that may not end in an approved project, but I think it is really essential. In addition, this process has works for us as a "filter" to avoid possible unwanted situations, observing details during this relationship that may active some "alarms".