IMproving spearmen if u hav enough mony is essential. They are qick to build and can be more damaging if given better training
When facing cave trolls, and the enemy keeps building them, do not attack[this is suicide, and also builds up power for there charg[trust me, ive had ugly moments where they hav to troll charges in the same few minutes]],but send scout around them
IF u hav good archer[such as the elves] for a start, upgrade close combat units]