I'm going to have to give a shout out for Panglot and his Janna - cause your girlfriend cant blow good enough guide. I used his guide and added a bit more AP and i spend my skills more for push, i also swapped Clairvoyance for Heal.

With AP runes you can kill all there minions in one Howling Gale and you can never go wrong with more mana if you don't have Clarity.

Every good Janna plays 21 utility. i also go 9 offense for the AP and 15% magic pen to negate items like Aegis of the Legion.

The trick here is to keep just enough AP to kill the minions with one Howling Gale while getting a bit more life and your boots. Always start with Rod of Ages, it is all around great for everything you will need. some people like to get Boots of Speed or even Mercury's Treads first. i myself might go for Boots of speed if i get in a lane vs someone like Master Yi. If you get off to a good start and land a few kills then you can get Mercury's Treads and still keep enough AP.

Howling Gale FTW. Getting one of each at first so you can cast Howling Gale and while it charges Eye Of The Storm yourself or your ally for the bonus damage then Zephyr the enemy champion to slow them making it harder to get out of the way of your Howling Gale. Also Eye Of The Storm is always great to use or fast attacking allies once to get to the enemy turret.

With Heal and Monsoon you can heal yourself and your team quite well and Flash is a great way to get away or get the jump on a enemy champion. You can also Flash after a turret shoots at you and before it hits you. All summoner spells can be good if you use them right such as Teleport or Dash to get back in the fight or stop a push. if you find yourself with mana problems you might want to get Clarity. Ive Save myself and my allies with Heal more times then i can count so i swear by Heal.

This build is all about being able to kill all the minion with one Howling Gale and still be able to get some kills. The cooldown of Howling Gale is perfect so you can cast it every time a wave of minions come.

Pros
Great push
Great at stopping a push
Can score kills
Can solo

Cons
Weak Eye Of The Storm at first
Weak Monsoon at first (but makes up for it with Heal)