A shepherd's primary tactic is sheer chaos. A perfect shepherd attack is an ambush, with as many animals as possible suddenly swarming the target. Flying and grounded species are often mixed to further overwhelm and confuse the enemy; in zero-g or underwater, a shepherd will attempt to attack from as many directions at once as possible. Shepherds are most likely to fail if forced to attack through a bottleneck.
A skilled shepherd, therefore, has an instinct for capitalizing on chaos. Some fight alongside their horde, usually with high speed augmentations and melee weapons. Others fight as one of their horde, puppeting or sleeving into an animal morph. Police units on Mars often swarm a location with police baboons, then flood the area with knockout gas, neutralizing suspects and baboons alike; whereas Martian rangers will send their animals forward an support them with sniper fire from afar.
Shepherd's often specialize in certain types of animals. Often, of course, there are environmental concerns; the hidden concern's shepherds usually use hellsquid simply because so few other combat animals can live in Ceres' seas. Most shepherds will still specialize, learning the capabilities of a few species as well as possible. Humans often use dogs, bearcats and primates, as do primate uplifts, but dinosaurs or terror birds supported by venomous birds are liked by neo-avians, while aquatic uplifts will typically favor aquatic animals.
Mercurial uplifts and particularly ferals are often shepherds, and tend to have a particular knack for it. Of all shepherds, they are most likely to directly puppet or sleeve into a morph that allows them to be one of the pack/flock/school.
When designing animals for a shepherd two factors must be balanced. Each animal, should, of course, be as effective a combatant as possible. At the same time, however, even heavily modified animals are some of the most fragile things on the battlefield, and more enhancements means more expense. Typically most animals are glass cannons, given only medichines to enhance survivability, with a focus on key offensive upgrades. Drug-glands, poison-glands, speed enhancements, complusion goads and, for those who can afford it, berzerkergang are all popular. The only thing more frightening than an attack by a swarm of baboons is an attack by a swarm of MRDR-crazed, venomous baboons who move twice as fast as you.