Cassiopeia is a fantastic champion to put effort into this patch. In top lane she has a dominant lane phase against most match ups and becomes very useful in team fights due to her presence with Deathfire and Rylais. She is also very potent against the Meta Top Laners and Mid laners Swain and Vladimir. Bear in mind however it is my opinion that Cass is better top lane than mid lane . This is because the champions she counters are basically perma banned and the mobile assasins that dwell in mid lane can make it hard for cass in lane.

Marks - We cannot buy sorceror's shoes therefore magic pen reds are essential.
Seals - I use armor seals because the primary role for this build is top. If you want to switch it for Hp that is also viable.
Glyphs - 10 percent cdr at level 18 is very nice on Cass and the remaining Glyphs make up for the lack of MR.
Quints- i use a movement speed quint to help follow up with more Es during lane. This is also beneficial when roaming.

Deathfire means the Q tick damage hurts a lot more. I take savagery to make last hitting a lot easier and Oppresor because we are getting rylais every game.

Top Lane - Tear into Rylais. Then void if they build MR , Randuins if they build AD , and Spirit Visage if they build AP. Finish Seraphs. Then buy rabadons. For your last item buy morellos if you bought randuins to compensate for the CDR and Lich Bane if you buy spirit visage. Lich Bane means we can push towers late game which cass has trouble doing. The percent movement speed is also very nice. Buying Randuins is good against ad top laners like irelia or wukong who stick to you. As it reduces their damage but also the active can help you escape .

Mid Lane - The same principle only replace randuins with zhonyas and Spirit Visage with Abyssal.

Zed - Go tear into Armguard , then rylais , then zhonyas. It is important in this match up that you do not die. Play defensive until he uses W.

Le Blanc - Play safe until tear , then use your Q on the minions to push them and kite back away from leblanc as you hit the minions to stop her getting in range of you.

Fizz - He can all in you at 6 , Farm sensibly for 3 or 4 waves and save your mana , bully him until you have enough for tear recall. After he hits 6 pull the minion wave and focus on farming.

Swain/Vlad - Tear into Morellonomicon and the match is over, try to land your Q and 3 Es should chunk around 40 percent of their health. Once Morellonimicon is finished they cannot sustain against the jets of damage you do. Look for roams bot lane with your Tp , you can ult the two bot laners and W to guarantee they cant escape. This is what you should try to do against champions with poor waveclear.

Rylais is an AOE slow so you aim your W on the team and if your team engages look for the enemy adc , Q them and E them twice. It should be a kill. If your team is engaged upon Ult to turn around the fight and go for the adc.

Strong Laning Phase, Strong Mid Game , Exceptional Scaling and Great teamfighting. Play it smart , practice alot and put Top as primary.