How about the Rockwell hardness test
Answer:
Keep flammables away
Explanation:
this would avoid anything catching on fire or burning down
Answer:
Conduct more trials.
Add less variables.
Choose a different person
Explanation:
More trials gives plenty of data to be examined.
Less variables makes for less confusion, and less things to keep track of.
Different person ensures that the experiment is not being done by one single person who could be messing up the data