Blitzcrank vs Nami

Fire Rocket Grab (Q) from a brush or a side angle: it grabs the first enemy hit, so you need a line without minions.

After a successful grab, cast Power Fist (E) right away: your next auto knocks the target into the air and deals double damage.

Sometimes engage without a grab: rush in with Overdrive (W), knock your target into the air with Power Fist (E), and save Rocket Grab (Q) for when they Flash away.

Use Mana Barrier (passive) to bait: at low health you get a shield based on your mana, enough to make a kill look easy.

In teamfights, save Rocket Grab (Q) for their carry and wait for them out of vision: grabbing them before the fight starts often decides it.

Change direction when she casts Aqua Prison (Q), then step up if she misses: it's her only stun outside her ult, on a 12 to 8 second cooldown.

Avoid trading when she casts Tidecaller's Blessing (E) on her ally: their next autos and abilities slow you and deal more damage.

Step out to the side of Tidal Wave (R): it travels a long way but moves slowly, and its slow lasts longer the more distance it has covered.

If you can engage, target Nami when she steps up: with no dash or leap, she can only walk away.