So you've decided that you want to play Karma. I have to admit that Karma isn't the strongest support in the game. So if you want a strong support, go pick Taric or Janna. Karma is a lot of fun to play though. What makes her different from most support is her ability to deal some good damage early game, and she is, apart from Taric, probably the 'tankiest' support in the game. If youve played her for some time, you shouldve had some nice escapes, because, as Phreak stated in the Spotlight: 'Karma is deceptively tanky'. This has a couple of reasons which will be explained below.

So, do you want to play a somewhat weaker support, which has early game damage and is more tanky then most other supports? Read the next chapter!

UNDER CONSTRUCTION

These are more or less stated in the intro, but heres a short overview:

pros:

• early game damage
• deceptively tanky
• cool playstyle regarding her ultimate
  
  cons:
• not very strong as support
• not very strong as AP Carry (this guide has got nothing to do with AP Carry Karma though)
• little hard to master

I haven't figured out how to make the icons yet, so im just gonna skip that part until I know how to.
So here we go:

(Passive):
Not a very great passive; early game you get up to 50 bonus AP, but i wouldnt rely on your passive. At its best, its a 1% extra for your heal, which means about 8 hit poitns. Her shield will increase by 40 points max., which isn't a lot either. Late game its not that much either, 140 max if you are at 0 hp. That means your heal gets stronger by 2%. A character with 3k health regains an additional 60 health do to your passive. Your shield will increase by something like 110 which isnt a lot either. So meh, the passive isn't great, but the idea is cool.

(Q-skill):
This is a good example from 'not very stong as support, not very strong as AP Carry'. It deals some damage in a cone and when combined with a Mantra Charge it also heals every allied unit in the cone. The heal isn't that bad actually, since the other heals got nerfed. Probably the biggest advantage over other heals is that you can heal your heal team if they're all in the cone. And it deals some damage as well. The obvious disadvantage is that you have to use a Mantra Charge. Its ratio for the damage is 0.6 so thats not very good. The deal isn't very strong either because it requires a Mantra Charge, so there you have it: not a very good support skill and not a very strong AP Carry skill.

(W-Skill):
This is one of Karma's two hardest to master skills. The buff and debuff of the skill are applied to your target and any unit touching the wire. So for this skill you need to pick the right target and your positioning needs to be good.
This skill is probably the main reason why Karma cannot be played well as a AP Carry: you need a target to apply your wire to and then move through your target. It doesn't deal damage to the original target.
Its a cool skill to use though. It can be used for chasing an enemy, by either slowing them or speeding up your allies (or both if used right) or for getting away. Combined with Mantra, its quite a powerful slow/speed boost. Without, its decent, but not great.

(E-Skill):
I love this skill. Its truly amazing. This is a great example of early game damage. The range of this spell is epic, and so is the range of the Mantra charged shield (its almost the same actually), which means you can harrass for quite some damage from a great range.
Also, together with a heal, a shield and a speed buff/debuff, Karma can be very hard to kill.
The most fun thing to do with this skill is shield minions Nasus is about to kill with Siphoning Strike.
Overall, its an amazing skill; it has a great range and harrassing with it is extremely easy (see also chapter: early game harrass).

(R-Skill and Ultimate):
Okay, so youre the only character that gains its ultimate for free at level 1. Use it wisely. You get one every ~30 seconds (it should be a little less due to cooldown runes and probably boots if you can get them fast).
Ill cover its 'how-to-use' later. Your ultimate makes your skills slightly stronger, but its limited to two charges at the same time. You can choose to either heal up your friends, slow/speed up things or deal AoE damage with your shield.
Mantra may seem easier to manage than it actually is. In your first games, you'll probably think: hm.. i shouldve Mantrad another skill there. But that's okay (if you dont have this, its okay 2).

First lesson about Mantra: YOU CANNOT HAVE 2 MANTRA CHARGES. Its a waste of time. As soon as you get your second Mantra charge, do something with it (there are some exceptions, but this is in general the best thing to do). Once laning phase starts throw out a Mantra charged on your enemy once you see a chance to do so. If you're teammate has got some damage and you get your second Mantra charge and enough mana, heal him up.

Lets talk about some situations:

• laning phase. You can do several things here with your mantra. Harrassing with Mantra + E and Q is an option. Heal your teammate with Mantra + Q, run/chase with Mantra + W, E and probably Mantra + Q
• You are on your own. Huge minion wave. And an enemy is attacking the tower. What can you do as a support. Ill tell you: Nuke the minion wave with Mantra + E and then Q. If your enemy is melee, hell get damage from your shield and your Q. If you W him (or her now that I think of it) the tower might do some damage to.
• You've overextended and get ganked. Combine your Mantra with W (Q if you really need it), but certainly not with E. Damage isnt very useful. Walk via the brushes, W your enemies if possible (as much as possible). If you find yourself low shield yourself and heal yourself up with Q + Mantra.
• Running with a teammate. Pretty much the same as if you overextend. If you W, try to hit your ally and as much enemies as possible, if you heal, be so kind to heal your teammate, and youve got a shield. Use it. Also, CV might give you a heads up on approacing enemies which might block a path you wanted to take (just like wards if you didnt forget to place them).
• Chasing an enemy. Mantra W yourself with as much allies as possible (if you can hit the enemy your chasing always choose for the enemy). Here, Use your Mantra for E instead of Q. Here you need only damage from the Q and the damage form your E.

This is my skill sequence on Karma. It is based on max survivability and early game damage. By level 13 you'll have 6 ranks in both Heavenly Wave and Soul Shield, giving you maximum damage output and healing in team fights.

For runes, I recommend taking 0/9/21. You can also go with 9/0/21 taking magic penatration to increase your early game damage, but I prefer the extra armor, magic resist and health regen from strength of spirit.
The 21 in utility is pretty straight forward; youre a support champion, take the CV and flash mastery (unless you prefer other masteries) etc. you probably know the deal.

I haven't figured out how to do the runes yet, by ill tell you which runes id use if i were you:

Flat AP Quints for more early game damage
Flat Magic Pen Marksfor more early game damage
Flat Mana Regen seals for... well more mana regen which is nice early game so you can harrass more
Flat Cooldown Glyphs so youre spells are ready earlier for harrassement, to save your teammate, yourself or to contribute more in teamfights.

What summoners spells are good for Karma.
I personally prefer Clairvoyance and Flash. Clairvoyance is good because you can follow the enemy jungler, check brushes youd rather dont facecheck, stop the enemy from doing baron/dragon, steal red/blue (and even dragon or baron if youre lucky)... Its very useful.
Flash is just OP these days (in Classic League of legends that is); you can escape certain death situations, finish kills without the enemy having any time to react.

Other possibilities are imo:

Teleport
To stop fkin Master Yi from splitpushing. Karma is the only support I would consider this useful on, since she can eliminate a minion wave very quickly (Mantra Shield + Q remember?). You can also recall and teleport back in lane to save your partner in lane if you're out of mana. Although this may sound graet, teleports has more uses then that (splitpushing is a very important one) and your team needs CV. Flash is also great to have.

Heal
Yep, summoner heal, the most nooby (or noobest, what is the correct word?) summoner spell in the game. But it gives you even more survivability. Heal, Shield, Heal AGAIN. But still I'd say CV and Flash are more useful. Flash is going to save you from most situations where Heal would save you, but not vice versa. And as I said: your team needs CV.

Your items really depend on your team.
Let's first talk about starting items.
You've got a few options here.
If the enemy team has a jungler, I'd definitely go with this:

Faerie Charm
2x Sight Ward
3x Health Potion
Mana Potion

Most of the games you will not go back before level 6, so you can get ganked. Wards prevent that. The potions are for more survivability and spamming and the Faerie Charm gives you even more mana regen and is one of the items needed to buy Philosopher's Stone.

If the enemy team doesn't have a jungler you have a few options.

If you're up against Soraka/ Caitlyn or something that's probably gonna kick your *** you can either grab:

Boots
3x Health Potion

or:

Regrowth Pendant
Health Potion

Imo, this is 100% about personal preference. I prefer boots 3 HPs. You already have health regen from Strength of Spirit (unless you go 9/0/21 ofc) and the HPs give you virtually 200 hp each extra in laning phase, which is nice. Boots help you get away faster. In the case of Soraka/Caitlyn lane you'll just dodge that Piltover Peacemaker or be out Caitlyn's insane range.
Take Regrowth Pendant if you think you wont get too much burst damage, but if your enemy can spam a lot for little amounts of damage, like Shen with his Vorpal Blade. Regrowth Pendant is also one of the items that builds into Philo Stone.

If your lane isn't that hard you can grab:

Doran's Ring

or:

Sapphire Crystal
2x Health Potion

or:

Meki Pendant
2x Health Potion

or any of the earlier given options, which aren't bad either to start with.

Take Doran's Ring if you're really feel like spamming that day. With your runes you got 30 AP right there at level 1. You also get 100 extra health and some nice mana regen. Take this item if you're planning on playing very aggresive.
With the other two choises, your damage will be less, but you've got more survivability with the HPs and you have more sustained damage/heals because you have more mana (regen).

Those are the possible starting items imo (remember to use the first option if the enemy team has a jungler).

Items you should get as soon as possible are:

Philosopher's Stone
Heart of Gold
Ionian Boots of Lucidity

You choose to play a support. So let your lane partner get the last hits. These items will still give you some gold, more sustainability and survivability. Philo Stone also gives you a lot of mana and health regen, which is very useful if your against soraka/caitlyn. Heart of Gold is just some extra health, which is never bad. And everyone needs boots 2. Why CD boots? You dont really need dodge or reduced CC because youre probably not the one going to be focused, neither are you build to deal damage with spells or autoattacks. CD is great for all your skills (mantra is also affected by CD).
Another option is Mobility Boots, if you prefer to walk around fast (to get back to lane, get faster to the troublezzz etc.).

So, you have youre most important items.
What's next? Because you are a support, it depends on your team.
Two items I consider a must-have on Karma are (ask youre team if they are going to build it):

Aegis of the Legion
Will of the Ancients

Aegis is great for the early and mid game; it gives you some health, armor and magic res. and damage, armor and magic res. to your team. Great to boots the stats of your DPS just a little to decrease incoming damage.
Will of the Ancients... ahhh I love it. AP and spell vamp for everyone (note: AD casters like talon and pantheon also benefit from spellvamp if they use an ability). This item is great in almost any game. Your whole team can regain health by using abilities.

Other items you can buy:

Shurelya's Battlesong I always build this eventually (provided that the game lasts long enough). You have that philo stone, and the item gives you health and a nice speed boost is used wisely (the regen isnt very useful late game).

Zeke's Harbinger nice item if you have two or three (or four, but then your team comp is usually just bad) champions relying on autoattacking.

Frozen Heart nice item if the enemy team has two of three champions relying on autoattacking. The mana from this item is also great.

Eleisa's Miracle this isnt really going to help your team, but if they have a lot of CC, this thing might be useful.