This can be done in the "Beggar's Canyon" training mission. In this mission, you will fly an X-Wing and have to shoot down enemy TIE fighters. The two minute time limit for this achievement starts when shooting the first TIE fighter. Make sure to use your rockets whenever possible. Your rockets kill enemies in one hit, but they take a while to recharge. When shooting the laser gun, you must aim the little white dot exactly on the enemy aircraft (so the lock-on turns yellow). With rockets, you do not need to aim as precisely, as it is fine if the lock-on is only red. It may take a few tries to get the "Best Star Pilot In The Galaxy" achievement, but fortunately the mission is really short.