Rome: Total War: Tips And Tactics

Council, how to quickly raise the rank of general and win big army with small losses.

We recruit the army: General, 4-5 detachments of dogs, a couple of detachments of the cavalry and infantry, can be archers.
Put before crossing or bridge over the river. When the enemy army attacks in battle mode, forward the dogs and archers. After the start of the battle, we wait when the enemy army enters the bridge, and let the dogs, at the same time, send dog trainers away from the place of battles so that they do not fall under distribution. At the same time, it is advisable to fire the enemy. By the time, when the enemy cuts all the dogs, his martial spirit and the number of troops will significantly decrease, therefore, we send a detachment of the general to the attack, which with 100 percent confidence sends detachments of the enemy to flight. Now it is necessary to destroy all enemies to one, thereby increasing the rank of general and its experience, can also be used by the help of equestrian detachments, if available.

The whole focus is that after the battle, if you take away dog coaches, and none of them die, the number of dogs is restored to the previous level, the same applies to the general detachment.
A huge plus is that the general with each battle has received new characteristics and, and later, even with a disadvantageous situation, he will benefit the battle by the combat spirit of his squads.

In principle, these are the tactics of protection, however, a stupid AI will persistently send more and more new detachments for your destruction, which will lead to the depletion of the resources of its fraction and subsequent destruction.