Actual experiment design is highly dependent on the phenomena being measured, and the data to be gathered whose analysis might confirm or invalidate the hypothesis.
Generally speaking, the steps are
Identify the hypothesis to be tested
Identify the data to be gathered
Identify the range of results for which the hypothesis is proven
Design the experimental setup (equipment, sequence, etc.)
Construct the design, and calibrate the equipment.
Run the experiment multiple times, using the same conditions, carefully recording the data.
Analyze the data, and do Do a reasonability check on the data. Data gathered multiple times under similar Conditions should yield similar results.
Consider having your design and data reviewed by a competent scientist not involved in your experiment.
Writeup your experiment and results.
