The objective of the experiment in your own words. Be sure to include the objective of each part of the experiment performed. This should be clear enough to be understandable to a person familiar with physics but not familiar with the details of the experiment.
Describe what you actually did to accomplish the objective.
A simple sketch of the apparatus. Include separate diagrams for different parts of the experiment, if appropriate.
Neat, well organized data tables. Include an explanation in words of what each quantity means and how it was obtained.
Calculations (including graphs if required) Clearly explain in words each step, stating why the calculation is being made.
Written analysis of the results. This includes a comparison of experiment vs. theory and an analysis of potential sources of error in the experiment.
Answers to questions mentioned in the laboratory write-up.