STAR

A very important learning as I was doing my MBA essays was that whenever you describe an achievement or failure, you should structure it in this way. It kind of kills the creativity, but acts as an effective checklist while writing a formal business communication.

S - Stands for Situation : Describe the basic situation that you intend expanding on.

T - Task : What was the task assigned or initiated by you. This is a specific thing like a deliverable.

A - Action : What Actions did you take toward fulfilling that task.

R - Result : What was the result of that action? Did it succeed because of something specific step or method you followed?
If it failed, what have you learnt from it. How do you say that you have learnt something?