1) The length of the wire needs to be measured and varied (this is order to get a complete set of results for your experiment )2) Then go through each length of wire and measure the current and potential difference for each wire. (in order to calculate resistance later )3) repeat multiple times for each length of wire in order to create an average = sum/n (if need be explain difference between accuracy and precision).4)calculate resistance using equation resistance * current = Voltage for each length of wire
Hazards: Electric shock due to current , overheating wire can overheat , can be minimised by using low currents.