Even if you have a great trainer, the course will probably be a flop unless the course itself is well designed. Conversely, even a poor trainer will look good if the material is good. By far the most important factor is planning. You have to find out what the students need to learn. In other words, what skills do they need to acquire to be able to perform their duties.
Some detailed research is necessary.
Tailor the course to suit the requirements of your students. The next part of the planning stage is to decide how to structure the course so that these skills are imparted. For example, how long should the course be, how should the topics be arranged, what practical exercises should be included, etc. Quality of the exercises is another key factor in good courseware. The exercises need to be simple so that the students do not get confused and they must illustrate the subject matter that you are teaching.