This build is a dedicated complete support Janna build. Janna is great to ensure kills for the carry or the mage. She is also great to break the opponent's team positioning.

Marks:
Going MagicPen marks for a little more bruising in the early laning phase.

Seals:
Mana regen/lvl for sustainability in the laning phase. More mana = more shields = profit.

Glyphs:
CDR simply because the itemisation isnt oriented towards CDR. These glyphs help getting these shields out faster. At level 18, by the time your shield goes out, you can put another one out.

Quints:
Flat AP for early game. Bigger shields early in the game changes the course of fights. its an extra 13.5 damage reduction on the shielded target. Wich is usefull when being harassed.

Going defence instead of MagicPen in offence. More armor, HP regen and MR to prevent being an easy kill. Plus, pretty standard utility build. Imp flash and CV and sacrificing 1 point in buff duration for the gold tick. Leaving the CS to the carry at bottom is a good idea so in adition to your philo stone your income should be descent.

The item build is pretty simple. Rush a philo stone for more gold income. Get standard boots for movement speed. Then you want to be a little more durable so get some health. Once thats done, get some more mana regen to be able to support the carry longer for the laning phase to finish.

Get an aegis, then the catalyst for extra health, mana and the level-up bonus. Get the shroud and finish the boots.

The rest is just preference. Movement for the team to help pick up kills or stacking time bonus from the rod or the banshee's for more protection if you get focused.

It's all about preference but this perticular skill sequence is all about supporting. I do not aim for damage. Wich is why i obviously dont level tornado first. Allthough i use it to set-up knock-ups, its not the most important part of this build but having one point in it is mandatory.

Zephyr and shields are the priority. Not leveling Zephyr enough makes it's damage ridicoulus wich is why i prefer evening out both skills. Makes up for a good slow with ok damage and some solid shields during mid-game.

Grab the ult when it's available obviously.

Summoner spells are also a personal favorite. Janna can use many of her skills as an escape but having one as a summoner spell is always usefull.

As a support, you dont try to steal kills from your carry so using ignite wouldnt be the smartest move.

Teleport isnt a good choice since you dont need incredible lane presence. Janna isnt about farming or harassing so it would be a waiste to run TP.

Revive isnt the best either since you already put points in shorter respawn time (-10%).

Heal, rally and smite can be viable. Yes smite. If you want to screw with the early jungle patern of the opponent you can smite the big wraith and leave or so. It also helps getting some CS off minions but remember to let the carry farm. Smite is also strong against heimer, annie or any other champion with minions.

The better choices exept escapes (flash and ghost) would be the following: Clarity, fort, exhaust, cleanse and CV.

Clarity is not my personal choice since i itemise and use seals for the regen.

Fort would be usefull but i just prefer vision over tower defence.

Exhaust can be used as an escape but chances are someone else is going to be running it and make a better use of it than you.

cleanse is verry great but most likely you wont be the target of stuns since they will want to shut down the nukers before the shields..

It leaves CV. Wich in my opinion is verry under-rated. Helping to secure jungle, cancel invasions and ganks, help ganking the oposing jungler, scounting brushes not to face-check them, etc. Vision is key in LoL and a good support should provide that for it's team. A wise use of CV can be defensive but also verry offensive. Clearly a good choice for the Janna playstyle that this guide offers.

Janna is a great support and brings alot to her team. Heals, shields, slows and knock-ups are all great abilities that will help the carries carry you through an easy win. Hope you enjoyed the guide and remember that Janna is one of the most powerfull support in the game. So play her smart and the team shall profit!!