Enchantress is a ranged intelligence support, jungler and pusher. She plays a similar role to that of Chen, whereby she converts neutral creeps to fight for her and then uses them to jungle, gank, and push.
Unlike Chen, however, she is capable of high damage output herself if left unchecked in fights, thanks to her ultimate.
Skills
Untouchable is skilled last but maxed second.
Enchant is always skilled first but maxed last.
Nature's Attendants is skilled second but maxed first.
Impetus is always skilled (levels 6, 11 and 16).
Items
Starting Items: Courier and/or Observer Wards, 2x Gauntlets of Strength
Early Game: Flying Courier, Magic Wand, Boots of Speed, Urtn of Shadows or Bracer.
Core Items: Power Treads, Aghanim's Scepter or Mekanism.
Luxury Items: Force Staff, Orchid Malevolence, Bloodstone, Heaven's Halberd, Scythe of Vyse, Black King Bar, Necronomicon, Shiva's Guard.
Situational Items: Hand of Midas, Drums of Endurance, Mekanism, Pipe of Insight, Boots of Travel.