Show results, not just activity
A weekly or monthly report is not a list of everything you did during that period -- it is a document that shows what outcome you produced against a goal, and what you plan to do next. Wherever a result can be expressed as a number, use the number; it makes the report far more persuasive.
Match the depth to weekly versus monthly cadence
A weekly report generally works best with detailed, task-level progress, while a monthly report is better served by an overview of the broader trend and a summary of results -- though the exact expectations vary by organization, so following whatever format is already standard where you work is the safest approach.
Frequently Asked Questions
Should weekly and monthly reports be written differently?
Weekly reports usually focus on detailed task-level progress, while monthly reports tend to emphasize the overall flow and a summary of results -- but it is safest to follow whatever format your organization already uses.
What should I write during a week with nothing notable to report?
Even without a standout result, spelling out the completion percentage of ongoing work and your concrete plans for next period shows that progress is still happening steadily.