What are the three topic types in DITA?

1. Task topic:  one procedure

2. Concept topic:  defines or tells how a process works

3. Reference topic:  has one type of reference info that users might need as they perform tasks.

You should try to separate the three content types so users don’t have to sift through unnecessary information.  For instance, if a user is looking only for the steps of how to bake a German chocolate cake, they don’t want extraneous concept or reference information such as the history of this cake in Germany or how it evolved throughout history to the current recipe.  They only want the task topics which are the steps in baking the cake.  

Most importantly, task-oriented topics focus on the users’ goals; not the way the product works.  You must write from the user’s perspective and in the active voice.  Target the appropriate audience and tells users why they need to perform this task.  Break up large tasks into smaller subtasks.