If he high wakes (jumps out of the system) you need a wake shift scanner to follow him. If he low wakes (back into supercruise) you can just follow him without scanning.
Power management is a big thing in this game. Set anything that is not required in combat to priority 5 or as low as you can get it, they will shut down when you deploy your weapons and save some power. Set your weapons to 2.
Also in PvP it is better to have 4 pips in systems, this will give your shields a bit of a boost, your weapons burn out quicker, put you’ll probably survive longer as a result.