There's really nothing Taric can do to you, just poke him down.
Not the most common pick, but it comes up now and then. She doesn't handle poke well and you out-range her. Just poke her down so she can't retaliate safely and you'll be fine.
A little annoying, but overall not all that difficult. She can't handle poke well and Inner Flame can be used to eat through Black Shield pretty easily.
Not super common anymore, but still an occasional pick. You can easily poke him down, he's squishy and immobile. Watch out for the double bomb stun and force him to ult himself instead of his carry if you can.
Low mobility and super squishy. Just poke her down to make farming risky and burst her in trades.
Very immobile. Just poke him down.
Annoying, but definitely not all that problematic. Use Inspire to help your carry dodge Rocket Grab if needed and poke him down.
Her poke can be annoying, but you dish out more damage and out-range her. Watch out for Crescendo post-six.
Pretty easy to handle early game, just poke him down so engaging you is risky. Watch out for his superior level 2.
Watch out for Zenith Blade and help your carry dodge it if needed. Poke her down so she can't engage safely.
She can deal a decent amount of damage, but her range is fairly low. Poke her down early so trading is risky.
A little annoying, but you outrange her pre-six. Your poke is better, but her CC is stronger, so care for that.
Reasonably low threat pre-six, mostly because your range is a bit better and your damage is higher. Post-six, she has a bit more of an answer to your burst, but if you play it right you can still win most trades.
Poke her down and she really can't do much. Poking her carry is fairly pointless unless you poke her down first. You will probably feel pointless playing against her and it won't be fun.
Pretty capable of dodging Soul Flare with Arcane Shift, so try to bait that out. He can poke, but he can't push. Just push him up to his tower and abuse that fact.
In a trade he can be pretty hard to damage properly and he dishes out a lot. Poke him down to make farming and trading risky.
Low mobility and somewhat squishy. Poke her down and use Inspire to help your carry dodge Zap! if needed.
Try to bait out rocket jump before bursting her. She does push a bit, so you can abuse that to put her in some risky situations.
You out-range her and can easily poke her down, but she can also poke you pretty hard.
Janna can't really pressure you at all, but she gives enough mobility to make dodging your skill shots easier and will be fairly hard to engage on. Just use Inner Flame to poke through Eye of the Storm and you'll be able to win most trades.
Poke him down and dodge Death Sentence. He can do a decent amount of damage with Flay's passive, so watch out for that. Think outside the Box post-six unless you want a rough time.
Decently mobile, but she doesn't have a lot of range and she doesn't handle poke well. Abuse your superior range and try to shut her down early.
He can't deal that much damage to you, but you'll also find him harder to poke once he gets Thick Skin. You have very little answer to devour aside from trying to snare him before he can get into range and speeding up your carry, so play this match-up carefully.
She can answer your poke with sustain, but her mana costs are higher and less efficient than yours. Dodge Aqua Prison and abuse your greater damage potential early. Post-six she has more of an edge, so be careful.
She out-ranges you and dishes out a lot of sustained damage. Watch out for Grasping Thorns and Deadly Bloom. She's much squishier and less mobile than you, try to abuse that.
His harass is easier get off than yours is, but your burst is higher. Try to bait out his ult if you can, since you don't really have a good response if you or your carry get caught in it.
Bait out Unbreakable and you can maybe win trades this match-up. Positioning can help a ton with this as well, but this match-up still sucks for you.
Longer range and she can just push you under tower. Avoid her traps and try to land as much poke as possible. This match-up is less than fun.
His mobility makes poking him a bit of a pain. He can also dish out quite a bit of damage, even now. Just try to dodge his skills and use Defiance to avoid the Culling if needed.
Fairly easy to hit with your poke due to his low mobility. His poke hurts though and you have to be careful when you or your carry are low since you have no interrupts for Curtain Call. You'll just have to rely on Defiance for extra defense and mobility against it, so good luck with that one.
Flash is generally a core spell, there's no reason to switch it out for anything. Exhaust tends to be a stronger pick throughout the game, as it gives you a massive damage debuff that is particularly effective against high damage assassins like Zed. Picking up Heal while your carry picks up Barrier is still a reasonably good option, especially if you take Revitalize. Ignite is a good early game option overall, but it can also be picked up against a high sustain team or against a high sustain support like Soraka.
I'm a support player (and not very good jungler/top laner) from the North American Server. I've been playing League of Legends since season one. My main champions in ranked are Nami, Karma, Lulu, and Sona.
Pros +good sustain, can counteract poke decently +good at establishing an early advantage +strong disengage +kites well, fairly safe
Karma has great poke and mobility, which makes her a strong pick against a lot of the popular supports. She is also more durable and one of the safest of the mage supports you can pick up. She can dish out a fair amount of damage on her own, which can be used to carry a lane if needed.
Karma needs to establish an early advantage in lane, lacks hard CC, and she doesn't have a particular power spike at level 6 like most champions. This can make it possible for a lane to be turned against her at level 6 (if she doesn't already have a strong advantage), which can be troublesome.
Cons -Generally needs to establish an early advantage -Lacks a true ultimate -No hard CC
Gathering Fire: This helps get Mantra up more often, which is pretty huge. Since Mantra has a fairly long CD (especially early) and gives Karma a lot of damage, it's important to remember to utilize auto-attacks and spells to lower its CD.
Inner Flame: This skill is Karma's main form of harass. It has a fairly small hit box, which means you really have to aim to land it. It has high damage, but the range is fairly short, so you may put yourself in danger if you're not careful.
Focused Resolve: This skill contributes to Karma's ability to lock down targets even further. It can also be used to bait enemies, as the empowered version heals Karma for 20%+ of her missing health, plus increases the snare duration by a good margin. You can also use this ability to help ensure the second hit of Soulflare lands if you time it properly.
Inspire: This ability has a lot of utility. It gives strong mobility to a single target and, when empowered, gives nearby allies a small shield and a speed boost (and gives a very strong shield to the target), which can be a very strong counter-initiation, disengage, or for soaking up a lot of damage on a single target who needs it.
Mantra: This skill empowers Karma's other skills. It has a fairly long CD at low levels, so should be leveled like a normal ultimate to lower its CD.
Currently, maxing Inner Flame first is the best option on Karma as it's her main damage skill and its CD decreases with each rank. I prefer to max Inspire second, for the increased movement speed and shield value. I then max Focused Resolve last, as its snare is effective even at one rank (though ranks do increase its duration). Mantra should be taken whenever possible, as the empowered abilities are increased in strength by putting ranks in it.
Starting Items Spellthief's Edge is currently the best starting item for Karma, as it works well with her playstyle. Ancient Coin is definitely a decent option, due to its superior gold generation, but you will notice a marked difference in damage if you decide to take it. All in all, both options are fine on Karma and what I use tends to vary based on the lane compositions.
Early game core Frostfang gives you even more damage and gold generation, so I generally recommend grabbing it right away. Always buy Control Wards whenever you can and try to deny vision to the enemy with them if possible. Remnant of the Watchers can help against high burst by giving you extra health.
Core Items As a warding item in some iteration is core on supports in general, mentioning it seems almost redundant. Eye of Frost or Nomad's Eye are decent to sit on if you want to wait on the upgrade. However, Eye of the Watchers and Eye of the Oasis provide extra health, among other stats, and the upgrades are fairly inexpensive. Oracle Lens is another core support item, that should be "bought" fairly soon after hitting level 9, as it allows you to gain vision control easier, which is important for keeping an eye on objectives such as Baron Nashor and Dragon.
Defensive Items These are the best defensive purchases for Karma currently. While Locket of the Iron Solari is not necessarily a core item, I find myself building it in nearly every game, so it gets a special mention here. It's one of the best support items, especially against a lot of AoE magic damage. Mikael's Crucible should be purchased against teams with a lot of hard CC. Randuin's Omen is a bit more of a selfish purchase on Karma, plus the new changes make it useful in a much more specific situation. 20% CDR is nothing to sneer at and Frozen Heart also gives a lot of armor. The aura is particularly good against AS heavy carries like Vayne. Zz'Rot Portal is an odd one, but it's quite good to grab on supports in general, even if Karma herself doesn't benefit massively from its stats. Redemption has a very strong active, plus the increased shield/heal passive and a mix of good stats for Karma. I find this item tends to be particularly good with Locket of the Iron Solari for mitigating burst when necessary, as it both increases the shield from locket and gives you the ability to simultaneously AoE heal your allies and damage your enemies. Banshee's Veil can be a very effective purchase against champions such as LeBlanc and Syndra, blocking part of their combo and generally giving you a nice bit of MR to mitigate magic damage.
Offensive Items Karma utilizes AP quite well, so her items often blur the line between mage and support. Liandry's Torment is particularly good against health stacking or tankiness in general, it also gives Karma a lot of damage and can be rushed if you're ahead. Morellonomicon is a great hybrid utility-offense purchase that gives a decent amount of AP to play around with. Twin Shadows is a nice item for Karma, it has stats she benefits from with a handy active that's quite useful in a number of situations. Ardent Censer gives you a decent boost to your shield's value, while also allowing you to give an AS boost to an ally or even your entire team if necessary. Athene's Unholy Grail is a decent purchase for Karma overall, granting a lot of CDR, mana and health regen, and a neat passive that she can quickly stack in order to give her allies extra healing. Zhonya's Hourglass is a nice hybrid offense/defense item that's definitely useful in some contexts. If you like to take the rune Perfect Timing, it's a particularly nice purchase as you get one of the item components for free (and it reduces the cooldown of the active). Shurelya's Reverie has an active similar to Defiance, which can allow you to use Soulflare more often in team fights. The stats it gives are also pretty decent, working well with other AP support items like Athene's Unholy Grail and the like.
Karma's function in lane is to provide poke, disengage/counterengage, and mobility. She excels at abusing early advantages, so press anything you can. Inner Flame/ Soulflare gives Karma a lot of damage and kiting power, while Inspire/ Defiance gives her strong mobility and counterengage. Focused Resolve/ Renewal gives even more chasing power, plus the ability to bait enemies. Generally you want to poke with Inner Flame, using Mantra for Soulflare to deal extra damage when positioning favors it. Use Inspire as needed against minor engages or to help an ally dodge things like Death Sentence (it has a short enough cooldown to allow for this against most champions). Against a full engage, you may want to use Defiance to either disengage or counterengage. You can use Focused Resolve in combination with Exhaust, Inspire, and Inner Flame to help peel for your carry if needed. Usually you should be able to keep bush control with proper warding; if the enemies stay behind their minions you might have to get creative with your positioning to harass properly.
Largely your function is the same, except now you'll sometimes use Defiance to disengage/counterengage or chase. You should still focus on using Soulflare to deal a lot of damage and hamper enemies, of course, but make sure you don't need to use Defiance before doing so. Focused Resolve can be used in conjunction with Exhaust, Inner Flame, or Inspire to help peel enemies off your carries (or yourself) if needed, but I wouldn't use Renewal unless you don't need to use Mantra for something else.
Remember that Gathering Fire lowers Mantra's cooldown when she auto-attacks an enemy or hits them with an ability. This is especially helpful early game, when Mantra has a much higher cooldown. Try to weave auto-attacks in between skills as often as possible to make the best use of this ability.
Against a team with strong engage, you can use Soulflare to hamper them and hopefully get some extra damage onto their back line. Defiance is better used as a counter-engage or disengage spell during teamfights, however you can use it to give an ally a massive shield that can turn the tables in a fight. Renewal is less likely to be used than the others, however it can be beneficial if you want to bait an enemy early or if you need the healing and can afford to use it. Its uses in teamfights are few and far between, as its range is significantly lower than Soulflare with none of the utility of Defiance.
Karma works well with most carries and team compositions, however champions such as Lucian and Sivir can push well early, allowing her to harass more easily. Lucian makes particularly good use of Inspire, as his highly mobile playstyle only can only benefit from more mobility. Jhin is a personal favorite of mine to support with Karma as that combination becomes quite strong after a few levels and Karma can somewhat make up for his lack of mobility with Defiance. In the case of Poppy, Inspire/ Defiance works very well with her kit, giving her a quick burst of speed she can use to catch someone off guard with Heroic Charge. In general, Karma works best with high mobility/burst carries, teams who like to siege towers, and teams with strong engages.
Zyra has a fairly significant range advantage over Karma, which makes her difficult for Karma given her damage output. Yasuo and Braum can be a problem for Karma in teamfights because they can pretty easily block Soulflare and Inner Flame with Wind Wall/ Unbreakable. Karma can gain an early advantage against an unskilled Braum, but her lack of hard CC makes it harder post-six. Karma struggles, in general, with champions who can ignore her poke or just poke from a greater distance.