If you haven't already, obtain a notebook to record all of your observations during your experiment.
Before starting your experiment, prepare a data table so you can quickly write down your measurements as you observe them.
Follow your experimental procedure exactly. If you need to make changes in the procedure (which often happens), write down the changes exactly as you made them.
Be consistent, careful, and accurate when you take your measurements. Numerical measurements are best.
Take pictures of your experiment for use on your display board if you can.

Box and Whisker Plot: A tool used to display and analyze multiple sets of variation data on a single graph.
Check sheet: A generic tool that can be adapted for a wide variety of purposes.
Design of experiments: A method for carrying out carefully planned experiments on a process.
Histogram: The most commonly used graph for showing frequency distributions, or how often each different value in a set of data occurs.
Scatter diagram: A diagram that graphs pairs of numerical data, one variable on each axis, to look for a relationship.
Stratification: A technique that separates data gathered from a variety of sources so that patterns can be seen.
Survey: Data collected from targeted groups of people about their opinions, behavior or knowledge.