With her enhanced basic attacks, which include firing vipers that poison the enemies hit and cause damage over time, Medusa gains a boost in attack speed.
When side strafing, Medusa incurs no mobility penalty, and when traveling backward, she incurs only half of the penalty. You need to focus on farming minions and earn a lot of gold in the early game.
You can use alternative items for Medusa as: Physical Power, Attack Speed, Physical Lifesteal, Physical Penetration, Crit Chance, Movement Speed, Cooldown Reduction, Mana, MP5.