Decisions at the outset of preparing a learner corpus are of crucial importance for how the corpus can be built and how it can be analysed later on. This paper presents a generic workflow to build learner corpora while taking into account the needs of the users. The workflow results from an extensive collaboration between linguists that annotate and use the corpus and computer linguists that are responsible for providing technical support. The paper addresses the linguists' research needs as well as the availability and usability of language technology tools necessary to meet them. We demonstrate and illustrate the relevance of the workflow using results and examples from our L1 learner corpus of German (“KoKo”).