Jayce vs Master Yi

In cannon form, fire Shock Blast (Q) through Acceleration Gate (E) from the start of lane: the orb gains speed, range and damage, and it's your best poke.

To all-in, switch to hammer: leap in with To the Skies! (Q), activate Lightning Field (W), then knock your target back with Thundering Blow (E).

Land an auto after each weapon swap: switching to Mercury Cannon (R) reduces your target's armor and magic resist, and your first hammer hit deals bonus magic damage.

To escape, swap weapons then walk through Acceleration Gate (E): Hextech Capacitor (passive) and the gate each give you move speed.

Against Highlander (R), don't run alone: regroup with your team, because he gains speed and ignores slows.

If you have CC other than a slow, land it right after Alpha Strike (Q): during the strike, he's untargetable, and Highlander (R) ignores slows.

If you have CC, interrupt Meditate (W): he channels it to heal, more at low health, and to reduce the damage he takes.

Put pressure on his jungle early on: Master Yi is strongest once he has his items, and each stolen camp delays him.