Medusa is a ranged agility hard carry. She is famed for being an ultra late game monster thanks to her powerful ultimate and Split Shot abilities, the problem is making it to the late game with her being in good shape; a tough ask given that her team will for the most part be fighting 4 on 5 for a good chunk of the early and mid game.
Skills
Split Shot is always skilled and mazed last.
Mystic Snake is always skilled and maxed first.
Mana Shield is skilled and maxed second, although a couple of points are often taken in Stats ahead of subsequent points in it.
Stone Gaze is always skilled (levels 6, 11 and 16).
Items
Starting Items: Tangos, Healing Salve, Circlet, Slippers of Agility, Iron Branch.
Core Early: Phase Boots of Power Treads, Magic Wand, Ring of Aquila.
Core Options: Linken's Sphere, Manta Style.
Luxury Extensions: Manta Style, Eye of Skadi, Butterfly, Mjollnir, Daedalus, Monkey King Bar.
Situational Items: Boots of Travel, Satanic, Black King Bar, Divine Rapier.