Part of instructions to his marshal when Imam Ali (a) sent him to a battle.
When you approach an enemy or when he approaches you, make it a point to keep your army on a hilltop or at the foot of a mountain or on the side of a river so that you easily watch the movements of your enemy. Do not involve the whole army in the encounter, allow only a few units to take part in the engagements. If your army is not on a hilltop then post your scouts and guards on high vantage points and along the line of fortification so that the enemy may not take you unawares.
Remember that the commanders of an army are its guardians and the eyes of these commanders are the scouts.
Try to avoid dissensions and do not cause superiority or inferiority complexes to take root among your officers and in your ranks. Wherever and whenever you camp, make it a point that all of your officers and soldiers camp in the same locality and are provided with the same comforts and conveniences and whenever you march, always march in company formation. If you want to rest during the night draw a circular formation of your lancers round your army and do not let sound sleep overpower you.