General Strategy:

 This is a more control/midrange deck that has plenty of ways to remove your opponents minions while generating tempo.  Priest doesn't have many win conditions anymore since Divine Spirit, Prophet Velen, Leeroy Jenkins, Mind Blast are all HoF as well as the major card draw from Northshire Cleric and Acolyte of Pain. This means that Priest either needs to find a deck with a win condtion or win through fatigue in a control deck. That's why highlander works so well in Priest because Zephrys the Great and Dragonqueen Alexstrasza provide that much needed win condition. Because Priest doesn't have any card draw we have to rely on solid value cards such as Sethekk Veilweaver, Madame Lazul, Mindflayer Kaahrj, Grave Rune, Skeletal Dragon, Soul Mirror, etc. 

Mulligan:

Always Keep - Everything 3 mana or less, except Shadowy Figure unless you have a deathrattle to use it on, don't keep Breath of the Infinite & Holy Nova except against Priest

I hope you like this deck and, as always, if you have any questions or have a suggestion please comment below (I respond to all comments)!

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