This is a difficult lane where you are constantly outranged and poked. Since Varus has no dashes, the active on W is purely for the movement speed and passive resists. Your goal is to survive the early levels and look for a specific window to use the mid-lane walls for a stun.

This is a poke vs. engage dynamic. Varus wants to keep you at arm's length with E and Q, while you want to find a wall stun to delete his low health bar. Since Q and E pass through or over minions, hiding behind the wave won't save you from his damage.