General

Kanna isn't meant for mobility, and if you're looking for a class that can hit hard real quick, you're looking at the wrong class. It's a heavy standstill mobber (evident in its 3 full map attacks and huge mobbing skills). For training prior to the Vanquisher's Charm Hypers, I would recommend just spamming Shikigami Haunting with a few Demon Furies because it doesn't consume as much Mana as spamming Tengu.. You CAN telecast with Shikigami, but in a huge crowd of mobs, I would just Demon Fury/Tengu Strike. Once you unlock all three Vanquisher's hypers (183, and yes, you WILL need all 3 to train effectively), you can consistently spam the skill with an occasional Demon Fury and Mana Balance. Orochi and Veritable Pandemonium (170 Hyper) are really good if you need some vertical range mobbing. It really helps me out when I do my dalies for Arcane River. The 150 Hyper isn't as viable, but it adds close-range damage for free. Once you hit 5th job, I definitely recommend getting Yuki-musume Shoukan. It pretty much allows you to go all out without losing HP or Mana. The attack rate is high, and the damage is pretty consistent with Vanquisher's prior to any nodes.

As far as bossing goes, you're only going to start doing well post 183 (with all three Vanquisher's Hypers). Use your barriers, be careful of bind times since you can't spam them anymore, and use Falling Sakura for bosses that have potion block. Also note there's a slight delay on teleport, so it's recommended that you also add Shikigami Charm (2nd job skill) to the mix. It really helps me out on bosses like Magnus and Vellum when they're about to do a 1HKO skill.

TL;DR

For training...
Prior to Vanquisher's Hypers: Spam Shikigami, Demon+Tengu for Horizontal, Orochi+170 Hyper for Vertical
Post Vanquisher's Hypers: Spam Vanquisher's, Demon+Tengu for Horizontal, Orochi+170 Hyper for Vertical
Post 5th job: Yuki-musume whenever available

For bossing...
Vanquisher's under Barriers. Be careful of HP, Bind, and Teleport Delay.

EDIT: Also if you haven't already, equip a fan onto Haku. It can potentially double your range.