Sven is a versatile melee strength hero. With a potent AoE stun, an oft-underestimated aura ability, and an ultimate that has the ability to more than double his damage he poses a large physical threat.
Skills
Storm Hammer is skilled and maxed first.
Great Cleave is skilled last but can be maxed second to maximise farm efficiency once the laning stage has ended.
War Cry is skilled second but often maxed last. Use before fights.
God's Strength is always skilled (levels 6, 11 and 16) and should be used in teamfights or to ensure kills.
Items
Starting Items: A set of Tangos, a Healing Salve, Stout Shield, 2x Iron Branches.
Early Game: Magic Wand, Phase Boots of Power Treads, Hand of Midas (if farming well).
Core Items: Armlet of Mordiggian or Mask of Madness, Black King Bar.
Luxury Items: Daedalus, Assault Cuirass, Abyssal Blade, Vladmir's Offering, Satanic, Heaven's Halberd, Heart of Tarrasque.
Situational Items: Drums of Endurance (early stats), Boots of Travel (late game 6 slotted).