well hello there !
I am the thijskelol, a current Plat 4 player in EUW.
And I am making this guide because this champ, really, like really helped me to get out of silver. She is not the strongest support anymore, but with some adc's she still is pretty good
have fun!

the preseason is here!

And it brings a lot of different, awesome things!

well if you are a adc or assassin maybe, but as morgana in the support role, you will not benifit that much from the new patch, maybe the new support items are kinda cool, but the masteries and other items don't really benifit the non-tank supports.

pros

most potential cc in the game !

can save an ADC easily, thanks to the black shield

amazing ult which can win teamfights

can build her tanky/full ap/utility so you can

adapt your build to what your team needs

amazing engages by flash; ult; zhonyas.

Not to hard to learn

cons

kinda squishy

no heal, what is not good vs poke teams

shield is less good vs full ad teams, it helps against cc tho

snare can be easily dodged

can be knocked away while doing ulti

is kinda useless when she has got cooldowns

quins

If u just start to learn her, pick 1 or 2 armor quins, more defensive stats is better when u don`t hit al your abilities.
When u hit your snares like 80% of the time, u surely can step to 1 arm quin and 2 ability power quins. That gives your botlane some more kill potential.
I am testing on using 2 movespeed quins and 1 armor quin. The movementspeed could be useful when u try to roam mid lane, and to dodge skillshots. But u got less damage and your early game will be kinda weaker

seals flat armor and flat health. I usually go scaling health, cause it gives way more health(starting from level 6, scaling gives more health then flat) but that makes your early game somewhat weaker.

glyph scaling mr (or flat armor, what seems the best to you in that situation).
U can also go for scaling abilily power glyphs, with some flat magic resist, I use them with the movespeed quins. so that I still do some damage in the late/mid game.

marks magic pen, or u could consider the armor marks, in case of a heavy ad enemy team, but usually magic pen is the best.

This is in my opinion the best combination for the mid game, certainly when u could buy zhonyas. thanks to the magic pen and extra ap u will deal tons of damage, snare/stun the whole enemy team and shield your carry. and the next thing you see is that you just won a teamfight... up to baron !

Well the new masteries... I think the AP support masteries are not so different from the normal AP masteries. But I could be wrong, I will give you quickly a summary why I have chosen those masteries.

Ferocity: Sorcery is kinda normal, you are a caster so you don't benefit much from attack speed.
Double Edged Sword is better because you are playing support, Feast is not good cause you have no guarantee you can kill a minion or opponent every 20 seconds.
Vampirism is meh, Morgana has got a lot of spellvamp from her passive, so you don't really need that, Natural Talent is not great either on morg cause you have no AD scaling. But maybe pick 5 points in Natural Talent it might be better if I think about it.
Oppressor is very good on morgana, you have got a lot of cc, so the 2,5% increased damage will be active most of the time. Bounty Hunter is bad on supports cause you are not supposed to kill opponents...
Piercing Thoughts welp again, no AD scaling, no reason to pick Battering Blows
The Last one is the most important one. But as a caster, you don't have much choice here... Deathfire Touch is the only one which is gonna increase your ability damage a bit. [Windspeaker's Blessing] could be nice, but that is in a whole other tree.

Resolve this tree gives you an extra bit of defence, and it will help you to stay alive in lane, why I did not take the Cunning tree? well, you could go this, but you will be a lot more squishy. And the Insight mastery is good on morg because you need your flash to do a good engage.
Recovery some extra sustain, you will not buy that much armor or mr, so Unyielding is kinda meh. It might be better at like mid/late game but the extra healing is needed in lane.
Tough Skin good in lane again, it will not do much late game. Explorer is decent if you roam a lot mid lane, 12 movement speed is quite a lot and you can use it to quickly rotate mid or help the junlger.
Veteran's Scars welp, just better than Runic Armor 4% health will not do much because you might have only 2500 hp full build.
Insight great mastery like I said earlier, gives 45 seconds less cooldown on Flash which is nice.

Ok. After playing some games with it, I feel that 18-12-0 is good. Maybe even better than the 18-0-12 I just explained. Let me give you the Cunning tree explanation.

Cunning: Wanderer is meh, good to roam a bit or to be faster in lane. Savagery is stupid on supports.
Secret Stash cookiiee, gives u some extra sustain in lane. 10% longer potions is nice.
Merciless you will have some small mana problems early game, because there are no mana pots anymore, so you could go some points in Meditation but Merciless is some nice extra damage. But if you have no mana you can do no damage at all, so you choose.
Bandit some nice extra gold, you will already get gold from Spellthief's Edge and this will give you even more. Dangerous Game this is a mastery I always liked, in bot you are in a duo lane, so if you kill 1, you will have to kill another, and there this mastery really can help, 5% missing health and mana is not that much, but could be good.
But Bandit provides more so I pick that one.

Ok, after playing even more, and hearing from streams and friends, I hear that the most optimal thing is 0-18-12
I would never go this way with morgana cause I like her with some more damage. But indeed, you are very squishy early game, and vs champs like Graves and stuff it aint good to be squishy... So if you want more info with these runes, here you go:
Well I explained most of those already, but hte Intelligence is very strong, 5% extra cdr, and you will be able to have 45% cdr. This is the closest you will get to The Old URF boyz.
In the last one you got 2 choices. Or Thunderlord's Decree like I would pick, or Windspeaker's Blessing . Well so The Thunderlord's Decree also applies on spells. So if you set your pool on someone, after 1,5 seconds, they will experience some more damage. It scales meh, but in lane it is good, because you have to trigger your Spellthief's Edgeso, double win.
The Windspeaker's Blessing is good to, you will not use your shield that much, but the damage reduction is very nice, it gives your adc some extra time to do damage, or to escape. This one could help win fights, but you will relly on your adc way more. In lower elo's, I would recommend the Thunderlord's Decree.

at start of the game

Pick always Spellthief's Edge and 3 Health Potion spellthief is easily triggered by your Tormented Shadow or just your basic attacks.

at first back

buy Sightstone as quickly as possible, but first upgrade your Spellthief's Edge, it provides some nice extra gold and damage. if you have got sightstone, you can switch your trinket to sweeping lens.

vs ad heavy

go for early Zhonya's Hourglass (certainly try to buy the Seeker's Armguard as quick as possible) and a Frozen Heart, it gives mana, and an attack speed reducer... I pick this one over Randuin's Omen but if you need the health, u can pick randuin's.
Also the new item: Zeke's Harbinger gives a lot of extra stats. and in the new season, critical strike is strong. so the passive is even stronger. If you can, try to buy this on as 3th or 4th item.

vs ap heavy

go cerainly for Banshee's Veil, one of the best items vs mages, and, if your jungler didn`t buy it, buy a Locket of the Iron Solari, it gives the whole team some extra needed stats during teamfights.

If u are the only ap in your team

If this is the case, consider buying more AP ofcourse, things like Rabadon's Deathcap, Rylai's Crystal Scepter and Morellonomicon are worth considering to buy.(apart from zhonyas, cause u should always buy that one)
But please don`t pick more then 3 full ap items, you will get to squishy and will not be able to do all of your spells and so you don`t deal that much damage in the end...

core

Sorcerer's Shoes or Mobility Boots, Sightstone, Zhonya's Hourglass.

Example build

Frost Queen's Claim, Sorcerer's Shoes, Zhonya's Hourglass, Frozen Heart, Rylai's Crystal Scepter, Zeke's Harbinger

always max your Dark Binding first, it will increase the time someone is snared and the damage will be increased. And this is your main damage and cc, so you'll need this most.
Black Shield second, cause you are not needing your pool to deal damage, or to farm, cause you are the support of course, your pool just costs to much mana. you only use it to trigger your spellthiefs passive

Dark Binding

at max level, this snare will last 3 seconds ! so imagine, the enemy adc, 3 seconds on the same spot, you only need a nidalee, orianna, or just someone with a grab, or high target damage, and it is a deadd adccc. so what now, enemy team?

Tormented Shadow

in lane you can use this one to gain money from your spellthief... but it just costs to much mana... and it will happen that you steal farm if you upgrade this to much... just not the spell you need on morgana as a supp.

Black Shield

so, the jungler comes in for a gank (amumu)... he wants to grab your adc... you shield your adc before the bandage hits. and thats it, amumu runs away, crying, poor bastard...

Soul Shackles

amazing, I call this. after 1,5 sec casting time, all the enemy champs still in the area, will be STUNNED for 3 seconds ! in combination with an amumu, orianna or malphite ult, you will have a good advantage in teamfights. also extremely handy in baron pit fights, just flash in, ulti, zhonyas, and let your team finish them... and baron..

like all the normal supports atm, pick exhaust and flash, flash is extremely handy and exhaust even more, do the exhaust on the enemy carry ( a fed talon, riven, caitlyn will do nothing if your exhaust them)
Some say that morgana has got already enough cc, and they pick ignite on her.... don`t exhaust is not some kind of cc.. ok, it reduces movement speed, but the main thing about it is that it reduces all damage that the target deals! which is way better then ignite...

thank you, and come again