Hello Summoner!
Welcome to my guide for support Janna. I find Janna to be a fun champion and I hope you do too. She is quite a good picked for competitive play and she is often seen in E-Sports. I have quite a good history with Janna with majority of my Ranked game wins coming from her.
If you have any feedback feel free to send me a message at Nflynn15@iskl.edu.my or post it in the comments.

The items included in this build are more tanker just because I feel that Janna is quite a squishy champion and she needs a bit of health to be effective, especially because her Ultimate requires her to be in the thick of the fight.

The reason that you should rank up her E ability first is because it is quite beneficial for helping get Golems or assisting your jungler by leashing blue, red ect. Not only can it be used well defensively, but It can be great for buffing your ADC to help them win trades. The E ability scales great with long range poke ADCs like Ezreal because when you give him the buff, he has a shield and more attack therefore his poke will do more. At rank 5 it gives the champion 50AD which is the equivalent of a B.F sword + 5 AD
Second you should max your Zephyr just because of the movement speed bonus that it gives Janna. Utility is one of her strong points.
Lastly the Q ability should be maxed because with levelling the ability it only provides damage and a shorter cooldown and the other abilities are more viable when maxed than her Q.

Her Ultimate ability provides healing and a pushback effect. This can be used extremely well in team fights but it can also totally ruin her own team. This spell makes or breaks a good janna support. It can be used to protect her adc, disengage an enemie or break their formation, spreading her enemies out providing for an easier fight. If she pushes the enemy champion into a wall or some sort of terrain it will stun them and this can be very effective, especially in the laning phase. Play Video Above is a fantastic of an amazing Janna ultimate which disengages kennen, making him totally irrelevant and negating all of his damage. Keep in mind that he used his ultimate ability which would have caused some heavy AOE damage. The janna pushed him back over the wall wich made the fight a 5v4, allowing CLG to easily clean up the remaining enemies.

The laning phase is crucial for a good game. This is where you aim is 3 things
1. Ward, Ward and Ward.
Warding is crucial and you should always keep your lane warded for map vision and to prevent ganks. Not warding is quite and getting ganked is quite a frustrating and frankly, easily preventable mistake.
2. Protect and Assist your ADC
You should communicate with your ADC so you know when he is going to trade. Skype or if you are in solo que, tell them to ping when they are going in or just try and predict when they will trade. Janna's E ability is one of her greatest assets and you need to take full advantage of it.
3. Assisting your Jungler Gank
This is where using your Q ability comes in handy. You should charge it up right before the jungler ganks to get a good knock up on them. The follow by exhausting the ADC. Your aim is to provide great CC to help with a kill, not damage. As a support you shouldn't get too many kills because you dont need much gold and a fed ADC is much more effective than a fed support.

Janna is a great utility support champion so remember to fully utilize her abilities.
Some of the key things featured in this guide are
1. Utilize her Ultimate ability
2. Protect the ADC
3. Warding
4. Assisting in ganks
5. Having Fun :)