The second table on this page contrasts descriptive aspects of writing with critical and analytical aspects of writing. For example descriptive writings states what happened, whereas critical and analytical writing identifies the significance of what happened.
As you read down the list you will note that for your writing to be critical and analytical you need to discuss not only what, but why, giving evidence and reasons. You need to show how information relates to other information and you need to evaluate importance and significance. And you need to draw conclusions that explain the importance and significance of the information. This will lift your writing so it goes beyond just describing information.