In terms of tactics, you do need to be mindful of damage output with dwarfs. Shieldbreakers in hordes, throwing mastiffs and shooting are a good source for you collection.
Dwarfs are slow and don’t usually get to charge first, which means that enemy units put damage on you first in melee, use shooting to make up for this before they get to you.
Also; you can read a review of Imperial Dwarfs (the list in the core rulebook) and Free Dwarfs (the ranger theme list in Uncharted Empires).
Shameless self plug; you can also read about my adventures with dwarfs and hopefully gain some insight into how the army works. 