Description is necessary, but keep it to a minimum. More important are Analysis and Evaluation.
Description involves reporting information, e.g.:
At this stage of writing, you are not analysing or evaluating. There is not much critical thinking going on here.
Analysis involves going deeper, for example, if you take something apart and look at how it functions you are doing analysis. In writing, you might be answering questions like "How does it work?", "Why did it go wrong?". So, your writing is not simply descriptive.
Evaluation literally involves assessing the value of something - how good it is, how useful, effective, appropriate, etc. In this stage, your "voice" should come across to the reader. Don't think of it as "giving the right answer" - it is giving your answer, based on your analysis and your understanding of the literature.
