This Electro Giant deck is a standard Egiant Beatdown Deck. Bide your time until you have an elixir advantage and go with an Egiant in the back. Support your Egiant with various support units and spells.
The Egiant is the main win condition of this deck, you can play him in the back to build a big push or at the bridge when their main counters are out of cycle.
It is important to pair the Egiant with the Golden Knight because the Egiant, Golden Knight Ability, Tornado combo is almost unstoppable.
The Mother Witch is great at applying pressure with her pigs. Use her against swarms.
In the early stages play passive and wait for the good opportunity to go with the Electro Giant. Usually, the best time to go for an Egiant is when your opponent is down on elixir and doesn't have their counter in cycle.
In the later stages of the game try to build up a large unstoppable Egiant push by supporting it will all of your troops and spells.