Karma has been one of my favorite champs - I play her as the support in a Kill lane bot. So far this works about 70% to 75% of the time. She is NOT a 0 cs support. She needs to clear minions and jungle creeps when she can. If your duo fails to get kills, then it's not as fun.
Build her like this:
Boot of Speed
Ionian Boots of Lucidity
Will of the Ancients
Aegis of the Legion
Rylai's Crystal Sceptor or Catayst into RoA or Chalice into Athene's Unholy Grail
Runes - Magic Pen Reds, Mp5/level blues, Flat AP yellows, either Move Speed or AP Quints
Masteries - 9/0/21 for spell pen, AP, cooldowns on Offense, and Spell Vamp, MS, mp/5, cooldowns for utliity (10% cooldowns from here) GET SAGE! You will get the most assists usually - healing your allies and hitting all the enemy will do that!
Spells: Clarity and Flash or Heal and Flash (depends on how much you like to spam)
Okay, my Logic!
Remember - this is a Kill Lane Support NOT your AP CARRY
My favorite lane partner is Garen. Why Garen? We hide in the bush, they run up. Garen hits Q and runs out like he's just been caught with another guy's woman and smashes them in the face - silenced! Now SHIELD BOMB HIM so he TAKES NO DAMAGE from their attacks and then he can SPIN TO WIN IN THEIR FACE or make a TACTICAL RETREAT. WHILE HE IS SPINNING YOU HEAL HIM AND DAMAGE THEM. The enemy will flash away!
His passive regen heals him up a bit, you laugh because now they have one guy at 1/3 hp. They will scream for their jungle to come down but he is trying to gank top so you're safe.
New creep wave comes in and they try to last hit and you SPEED BUFF GAREN WITH HIS Q AND HE SMASHES TEEMO IN THE FACE AGAIN, YOU SHIELD BOMB AND THROW YOUR FANS AGAIN - A smart Garen takes Exaust and Ignite so now this other guy, who I apparently decided was Teemo, is now DEAD!
You share the farm and you as Karma PROBABLY KILL STOLE BUT THAT'S OKAY!!!
Now you're level 6 which means IT'S TOWER DIVE NO MATTER WHAT BECAUSE YOU CAN'T STOP A GAREN WHO HIT HIS Q SO WHEN HE RUNS IN YOU SHIELD BOMB HIM AGAIN AND WATCH AS HE ULTS THE little GUY.
Philo for sustain - Shurelya's Reverie + speed boost is insane + Garens Q = LOL.
WotA for great life steal and Aegis to make your shield even be able to take more damage and help everyone's resistance in a Team Fight! If you get a deathcap then your Shield bomb should be over 600-700 or so, especially if you drop to low health and your passive kicks in.
Bomb the initiator and heal when necessary, shield the carry, speed boost the entire group, etc, Karma can do it all.
If your Garen partner is Drunk you will probably get more kills - YOU HAVE TO BE AGGRESSIVE.
REMEMBER IT DOESN'T WORK AGAINST EVERYONE ESPECIALLY A PAIR LIKE SORAKA + VAYNE WITH THE HEALZ AND KNOCKBACKS.
DON'T SAY IT SUCKS UNTIL YOU TRY IT!
OTHER GOOD LANE PARTNERS INCLUDE: Renekton, Irelia, Jarven, Panth, and Talon - They have good gap closers and take take some hits - it's all about burst.
Please let me know if this strategy works out for you. Add me in game to try it sometime.