Here is my Morgana build. There are some notes mixed in for some of the not-so-normal choices. Comment if you have feedback or questions. With experience, you should be able to pick up on situational choices as well as know what to do with a build. Enjoy!

Pros: Morgana is hard to counter against as it just takes lots of patience on the other team's part. She also brings more offensive abilities than most standard supports, as well as a shield for the ADC. Ultimate is very useful in close-quarters team fights.

Cons: If you have an off game with your Binds (Q), the bottom lane can get ugly. Must try and keep the balance between offensive bite and some tankiness to help in fights.

I usually go with Exhaust and Flash. Occasionally, when I want to be more offensive oriented, I go with Ignite. Adds that extra bite in the bottom lane.

I try to get all of the abilities to level two before maxing out any of them. They all can be useful, and by that point you will know if your team is going more defensive or offensive. If going more offense because you are up early, max out the binding (Q) first. If your behind and going more defensive, I suggest maxing the shield (E) first. This way you can help your teammates out sticky situations, or you can flip the game by throwing it on yourself and using your ultimate to initiate/impact a crucial team fight.

Short story here. At first, build a mix of ability power and defensive items. That is why I suggest Zhonya's Hourglass and Mikael's Blessing first. Then, like with abilities, you can specialize after reading the start to the game. You can continue to go defensive with the Frozen Heart or Banshee's Veil. If it's not clear yet, go with Locket of the Iron Solari next and wait it out a bit more. If it' time to push on offense, then go for Rabadon's Deathcap and the Void Staff.