also blitz, thresh and such are good for your wall to split them from their team due to that it grows over 3/4 of the lane at rank 5 also its good AGAINST naut as his dredge line will hit the ice wall and pull him to the ice wall.
also a few hints on game play
your q travel and activated q stun count as two spells and can do its damage twice.
your ult does damage per second as well as when its deactivated so if you shut it off right after a damage tick its basicaly a double tick.
dont feel to scared with your passive up, play aggressive at lvl 1 and 2 and dont feel bad about trading your passive for first blood on them.
rush for a tear and then ROA and if you recall and are buying just sit in the fountain with your ult active to freecharge tear.
you dont need much ap so dont worry about rushing ap early game.
swiftness boots are your friend since you're super slow.
use your ult as a zoneing tool as well people will actively try and move away from it, due to both the slow and damage. your e has low range but almost instant cast time but try not to use it unless your get a q or ult slow so it will do the double damage.
practice CSing with her as it is difficult and you will need mana early game.
your wall can split people apart obviously. and a god placement can save an ally from death at the hands of a fed garen or making garen run 4 laps around the map to get back at you.
even at lvl 1 your q will stll mess with enemy players pathing and can let you get a free q+e off since your q moves fairly slowly.
if your giving up your passive for a kill or an enemy gank make sure yo're under tower since you get reduced armor/MR and can't defend yourself. for 6 seconds.
your passive has a 5 minuet CD so as long as its down be careful.