A client brief or any document that details what are the client needs and their objectives or goals that they want to achieve with this project. It is necessary because it will give the creative team perspective, clear information and a path to follow for the conclusion of the project and successful results.

A clear strategy of how the project will start, develop and conclude with a defined timeline, this will give an advantage because you have a process, therefore you won't waste time which can lead to stressful situations in case the deadline of the project is close and you don't have what was required. In that case a process will give you time to make a plan b. 

 

Planning is also really important because it carries insights from users in general, helping the creative team find the unique selling point of the client's product and helping reach its target audience.