Welcome to my Guide!

Pros:

+ If rigth played a awesome burster
+ mid game easy farming
+ good substain and stun
+ OP-Combination Liandrians + Q-Spell

Cons:

+ Hard to master her
+ low manapool
+ early game farm is hard

Normal runes: armor and magic resist allows substain against a jungler and you have enough resist for your opponment on the mid lane.

magic penetration is the best way in early game to poke / harass your enemy

15 Ability power combined with the masteries are a great start for your lane.

Hello,

in these chapter i would to explain, why i choose my masteries.

Normal ability power masteries with 4% Cooldownreduce 18 AP with Level 18 and other basic stuffs
Other points are placed in defense for more health and magic resist against your ap enemy on your lane.

Hello,

In these Chapter i explain how to play cassio in her lane. She is a snake and have much poison!

At start you have great abilities to poke your enemy if you hit with your q try to use your E-Spell after it and poke only with this combination, if you successfull try to kill your enemy this way.

If you reach level 6 use ONLY your ultimate if the enemy is spotting you ( means look in your direction ) and start it, use q and much E E and refresh the early cdr after every second E-Spell

Thats the most of it, i think W-Spell is really useless....^^
.

In this Chapter, i explain why i choose this items!

Like above mentioned you start wit boots and 3 healpots. With your masteries and runes you have enough substain to hold the lane and easy farm, after that you try to rush liandrins so fast as yo ucan, cause the pokes have a heavy increased Damageoutput like before. ( If Enemy build rod of ages or similar you do more dmg )

Now you have much magic penetration and life after that you increase the dmg of liandrins with rylais. you get a slow and you can easly chase your enemy.

Now you have to go on damage and you buy rabadons, deathfire grasp and void staff, then you have 30 + 50% Magic penetration, much Ability Power and you can burst horrible with Deathfire Grasp

In this Chapter i explain the teamfights,

Cassiopeia is a really strong champion with much aoe damage over time attacks that make you easy to poke and with a right placed ultimate you can win a teamfight easily.

Cassiopeia ist good with:

+ Amumu
+ Leona
+ Sejuani
+ Varus