In the mulligan for this deck, you want to look for Fire Fly, Jade Claws and early game synergies such as Tar Creeper and Tol'vir Stoneshaper.
Only keep Fire Plume Harbinger and Murmuring Elemental if you are playing second and have a clear plan available to properly utilise those cards.
Against Secret Mage, you should keep Servant of Kalimos and card draw such as Mana Tide Totem to get high cost, high damage elementals for the mid-game, such as Blazecaller and Kalimos.
Paladin (Silver Hand/Murloc)
Against aggressive decks such as Paladin in the current meta, you want to look for Tar Creeper, Tol'vir Stoneshaper, Jade Spirit and Lightning Storm.
Against Cubelock, this deck relies on all of it's removal abilities, such as Lightning Storm, Hex and Volcano.