From wikipedia:

1. Define a question

2. Gather information and resources (observe)

3. Form an explanatory hypothesis

4. Test the hypothesis by performing an experiment and collecting data in a reproducible manner

5. Analyze the data

6. Interpret the data and draw conclusions that serve as a starting point for new hypothesis

7. Publish results

8. Retest (frequently done by other scientists)

Emphasis on 4) and the "reproducible manner".

Otherwise what's the point really? We would resort to trust or belief in one's sayings.