Dwarfs are small creatures that live under mountains who seek wealth. But also they are good warriors. Here are some tactics.
Tactic 1.) The Axes of Durin.
Tactic 2.) Playing by defence.
Tactic 3.) Rangers.
Tactic 4.) the elite troops
Tactic 5.) Allies.
Tactic 1 basically means that it is a mainly warrior army. The army is good at taking out big enemies like trolls and dragons. It means that you have to include as many 2 Handed weapons as possible and use your best hero to win the fight. You will crowd round the enemy. This is only good at taking out big enemies.
Tactic 2 relies on the high defence of the warriors and heroes. Basically you make a giant shield wall and protect the archers from threats like bows and crossbows. (Orc bows kill on a 6 followed by 4 on the shield wall, instead of 6, and crossbows on a 6 not a 5.), so the dwarves are pretty well protected.
Tactic 3 is a good force able to use their bows and throwing weapons to the max. It also is the best tactic for getting over difficult terrain.
Tactic 4 relies on you splashing out a bit more money and points for a lot better warriors. Think of Kahzad Guard as Dwarf warriors + 2H axe, but with 1 more defence, 1 more strengh and the bodyguard rule. Think of Iron Guard as Dwarf rangers + throwing weapons, but with an extra attack, strengh and defense. And then think of the vault warden teams as what you wanted. (Spears, and a defence of 9 at the front.)
Tactic 5 relies on you mating up your dwarves with another force. (Obviously.) Use Legions of Middle Earth for guidance of who to ally, or the Kahzad Dum Sourcebook.