Play with a CC team to increase the potential of your passive pull.

Great combo's with adc's as:
<3 Draven, great with his E
Ash, Arrow stun and you can pull right away.
...

Vayne, Look out that you dont right click to fast, let the enemy get stunned at the wall first.

These are your main items. Liandry's will boost your damage like crazy turning your support role into a full ap tank damaging beast while supporting your team with great cc combo's.

Instead of maxing (Q) you want to max (E) to enrich your role as an OP CC support.
Use your (W) to scout in the enemy jungle (blue or red buff), bushes and most important use it to change your opponents paths. Place it in the path of the enemy to slow them or use it so that enemy's cant run away they will have to run into the slow effect or walk around. Both creating a nice adventage.

There is great CC combo's possible, with super combo's if the team has cc 2. Most of the times I create a great situation by using my E on max range, hitting a minion on the way back that stands next to the enemy adc. Or I wait for my adc CC attack and I pull with my E right after. The ultimate support tool is your E becouse you can cc multiple enemy's while they are behind a big minion wave or even a tanky support just cuz the stun triggers on the way back.

I have found myself best with these runes just because I have this build for full CC support role and one for a bit more damage support role (with maxing Q). You can change around to (Glacial Augment) for example, but this one gave me the best results in a full support role.