If you do not know how to write a case study, then you are at the right place.
First point to note. Identify a relevant issue to write on. Having a lot of issues in one case study-hmmmmm not a good idea. Here you need to display your ability, firstly, to have a good understanding of the business subject (strategy, ethics, finance, governance, HRM, Marketing, innovation …) you have chosen. Identify a company which is relevant to this subject. News items, business magazines, management articles are a good source to start of with an idea. After you have identified an issue to write a case study on, start analysing. Here company information is crucial to analyse the strengths, weaknesses, opportunities and threats, yeah yeah you guessed it right, DO a SWOT Analysis.
Identify the key players (could be the marketing manager, product manager or the CEO)central to the theme that you are building the case upon. More to follow