This chapter deals with the fundamentals of corpus compilation, approached from a practical perspective. The topics covered follow the key phases of corpus compilation, starting with the initial considerations of representativeness and balance. Next, issues in collecting corpus data are covered, including ethics and metadata. Technical aspects involving formatting and annotation are then presented, followed by suggestions for sharing the corpus with others. Corpus comparison is also discussed, as it merits some reflection when a corpus is created. To further illustrate key concepts and exemplify the varying roles of the corpus in specific research projects, two sample studies are presented. The chapter closes with a brief consideration of future directions in corpus compilation, focusing on the importance of compensating for the inevitable loss of complex information and taking the increasingly multimodal nature of discourse as a case in point.