This build is mainly for me, to be able to see what I want to do. Then I understand it can be weird. You can also comment if you want.

This build is to be a nice support who doesnt die. (mana + hp).

I tried it sometimes : 0/1/8, 2/2/12

But as a support you need a good mate and not a ******-one.

Armor : to resist and use more your spell (because you live longer)
Mana : cast more often

That is Masteries Page I use for support.

First point in the attack spell to harrass.

Then max the Speed/Heal, I love it. It heals very good even without ap at early game.

Then max the slow spell.

(Of course upgrade your ulti everytime when you can)

Flash to avoid death.
Clairvoyance to reveal ennemies. ( you are support )