Currently 10-1 from rank 5 to 3, deck seems to have potential. Try it out, it's a lot of fun. Feedback is appreciated.
mulligan aggro: look for mistress, tar creeper and sometimes hellfire, you can hold ancient watcher if you have a sunfury as well.
mulligan control: look for value cards like twilight drake, its good to hold some early game as well for pressure.
against most aggro decks you can stabilize with early game minions and if you have enough time to taunt a mountain giant, it's pretty much over.
against control try to make big swing turns by shambler with twilight drake / mountain giant. jaraxxus is a huge part in control match ups especially taunt warrior. you have to be able to put out an early jaraxxus and drop 6-6's until they're finally out of removal.
if you have any specific questions let me know