So uh, I havent found a guide for support Karma the way I play her so I have made one to share success. There is only really one key difference that I have to other guides and that is the use of spirit visage (I will explain later why I use this).

Good poke with slow
Shield and speed boost
snare
can heal self
Lvl 1 ultimate

squishy early levels
cannot heal adc
no instant hard cc
underrated

I run a slightly strange set of masteries with 13/0/17 however there is a reason for every placement. 13 in the offensive tree gives cdr, some extra ability power but most importantly the dangerous game. In the late game as a support you will hope to get at least 3/4 assists in a teamfight. this can mean up to 20% extra health and mana.

the 17 points in utilities are mainly for the laning phase for the extra gold, mana regen and cdr on your flash and exhaust.

morrellonomicon is an extremely useful item for any mage for the unique passive of healing reduction. combined with is cdr, mana regen and ability power you couldn't go further than this for a first full item.
The spirit visage is an amazing item for any healing champion, when combined with Mantra-Focused resolve gives an insane amount of healing. Usually this alone also give enough magic resist to force magic based assasins to look else-where. without this threat of immediate death in teamfights you can usually get both halves of the healing.

Basically, use your q as often as you can and try to hit the carry's as poke. Shield your carry's and help peel for them. If your shield is on cooldown or you just need a little more then use your w to snare the anti-carry.

Karma is a beast support because of her ability to buff her whole team with shields and move speed and slow the entire enemy team and zone them hard. who ever said you can't carry from support.