Welcome to my Support Karma guide.
This guide is based on the Champion spotlight, so not all ideas in here are mine.
Though I've been playing Karma for a while now, there still may be some flaws in the build.

P.S.: This is my first "real" guide i made.

The gold/10 quintessences are quite logical... a support build needs a steady income.
The CD-reduction glyphs are there so you can use your Mantra more in early game,
and as you will notice it ensures that your CD-reduction is capped when all items are bought.
To make sure u can lane longer there are the MP5 seals and the HP/level marks.

The skill sequence is made so that you can get to your lane as fast as possible with the Spirit Bond. Normally I go bottom lane. To get there faster with my teammate i cast the Spirit Bond on him. If you're going back in lane with a creep wave next to you, you can cast it on the leading creep to get back in lane faster. Further on I max Heavenly Wave for the heal, followed by Spirit Bond and the Shield. I actually use the shield the least because the Mantra aspect is not really supportive but rather offensive.

For items start with the Doran's Ring. When u have to get back to base u should have enough money to get at least the Philosopher's Stone and maybe even the full Mercury's Treads. Up next is Shurelya's Reverie followed by the Spirit Visage for the increased healing effect from your Heavenly Wave. A normal game would go long enough for you to get a Soul Shroud, completing the CD-cap and giving that nice supportive aura for your team. And if the game is really taking a freaking long time you can get the Will of the Ancients, Granting some extra damage and healing as well as some spell vamp and AP for your teammates.

For summoner spells i go Teleport and Flash. In that order so i don't accidently activate the Flash instead of the Teleport ( this happens a LOT to me =( ). Teleport for the map control and getting back in lane easily. Flash as it is a must have in any situation.

As a support role you should try NOT to get last hits as this will ruin your carry. Just hide in the bushes, heal your teammate if needed and cast the Spirit Bond on creeps to get them low.

Karma is Excellent with a hero that has a stun or slow OR has a quick damage output, as you are most likely to get first blood with the slow from the Spirit Bond ( I played a few games with a Nocturne, granting us first blood every single game =) )

Well, that is my guide.
Thanks for reading it and i hope it actually helped you out.
Make sure to leave a comment for this is the first guile i ever made xD.