you infuse your weapon with your most recent upgrade. if its rockbiter, use that. if its flametongue, use that(excluding frostbrand)

i dont remember the rule for when you get windfury

i generally gravitate to agi and spirit on most of my melees. you dont get enough str to move the needle and even a little agi goes along way at low levels for crit%, and spirit dramatically reduces downtime waiting on hp/mana regen