In order to earn a doctoral degree, a student is expected to complete a certain amount of studies, write a doctoral dissertation and defend the dissertation in public. There are many ways of completing doctoral studies. It may be sensible to avoid chasing credits and completing impulsively random courses that may not be linked to your research in any way. Instead utilise your doctoral studies to broaden your understanding. As an example, near half of the studies could relate to your research topic and the rest could broaden your knowledge base. In any case, try to avoid a situation where, after finishing all your doctoral studies, you do not have the theoretical base needed for your dissertation.
If you prioritise earning your doctoral degree, aim to organise most of your activities to serve the realisation of your doctoral dissertation by integrating the earning of the required credits and the application for research grants into this process. To maximise the effectiveness, avoid courses that do not support your research. Select courses so that they are somehow related to the subject matter of your dissertation. Too often a doctoral student makes the mistake of taking courses that are interesting, but do not support the dissertation work in any way, or take all the courses before even considering the doctoral dissertation. Earning the required credits is typically not a problem, therefore concentrate on your own learning, progressing your dissertation and collecting relevant material.
In order to learn to write and publish, you may wish to switch into writing mode as soon as possible, already when earning your credits. You can, for example, study books and recent scientific articles relevant to your research. Instead of verbal exams, favour completing studies by writing summaries of books and articles. Professors typically accept written summaries as doctoral studies. Furthermore, you can later utilise some of this material in the theoretical parts of your dissertation.
You may also be able to get credits/partial credits for articles that are not directly related to your dissertation. This is a good motive for taking part in co-authoring colleagues’ articles and taking part in their writing process. For the articles that will be included in your dissertation you cannot obtain separate credits, but for other articles you may. However, there are some differences among different units within Universities, so you will need to check with your professor/faculty what they find acceptable