Objective

In a few brief sentences, clearly explain the main goals of the experiment.

Procedure and Equipment

Explain how you performed the experiment. Include sketches and/or photos of the apparatus. Include enough detail that another student in the course could repeat your work exactly.

Data

Record your data and any extremely simple calculations here.

Analysis

Record here significant calculations you needed to perform in order to analyze your data. Any graphs you created should also be in this section.

Results

Discuss here the main results of your investigation. Mention significant sources of error (and where possible, which sources matter most).

Conclusions

Draw conclusions based on your results. 
Your conclusions should link back to the objectives of the experiment in a very obvious way. 
Remark on any discrepancies between your results and what one might expect (always taking account of experimental uncertainties; your standard for "agreement" between theory and experiment must be whether any two values agree or not given their uncertainties and not whether they are the same within some percentage or some absolute magnitude. 
Also include any suggestions for improvements for the experiments, whether in terms of equipment or the procedures you followed.