The right design brief should both challenge and inspire a designer to produce incredible work. It's the guiding light for the project.
It's all too easy to assume that you know what the client is thinking, and failing to ask the right questions at the beginning can lead to a disappointing finished result. To avoid that, spend time filling out a design brief alongside your client.
A great brief contains an overview and scope of the project, the objectives and goals for the design, information on the target audience, budget, timeline and key milestones, examples of existing design work, and finally, guidance on what to avoid.