Win fast, or wait for Dragons. A lot of grenadins will help to block non-overwhelm units. Spells will help to handle very tough enemies. Piercing Shots and Torches is great help against units w/ lifesteal. Flash Fires and Dragons great for end-game.
The ShiftstonedEternal Power Calculator is a deck-building tool that visualizes your odds of drawing enough Influence and Power based specifically on the cards found in your deck.