Karma is a very strong support for kiting / poking. Play her if you enjoy being annoying! She is most effective in a strong kiting / poking comp, so if possible try to pick her in a comp that has good poke. I recommend picking a more all in champion, such as Leona or Annie if your team lacks poke and would rather just brawl. Anyway, check out how I play her:
Inner Flame is your primary damage dealing ability, and is maxed first for high damage harass. Inspire is an extremely strong shield that becomer AOE when Mantra'ed up, so maxing it 2nd is certainly correct. W is somewhat of a one point wonder, so leaving it at level 1 for most of the game does not hurt you very much.
Attempt to push the wave with auto attacks as much as possible. Use your Q (Mantra'd as much as possible) to harass down their ADC or Support, and try to get the wave pushing on their turret. Karma is the most effective support at harassing down enemies under their turret, and you can cause the enemy ADC to miss many creeps due to your high pressure.
Karma is not a super effective ganker, due to her squishy nature and lack of really hard CC. I recommend mostly getting wards down and staying with your ADC, and trying to push down turrets. Once you guys get the turret bot lane, you should rotate to mid lane and try to harass them down under turret and slowly finish turrets.
Karma is quite effective at grouping, as she provides a large amount of mobility to her entire team with Talisman of Ascension and her Mantra'd Shield. I recommend staying with the large part of your team and attempting to poke the enemies as much as possible. Always be ready to use Talisman and Mantra'd Shield to help your team engage, or to allow your team to run away from an engage.
During teamfights you should be Mantra'ing her shield as much as possible, as an AOE shield and speed boost helps immensely. You should be spamming her shield on to your ADC as much as possible. Use Karma's W on any melee champion that tries to get on to you or your ADC, and use your Q to help your ADC kite any champion trying to get to him.
I hope you liked the guide! Karma is an extremely strong pick in the current meta, especially if you can get a good poke team comp to run with her! Ask me any questions on twitter! Twitter @LemonNNation and facebook.com/LemonNationLol