Hello, this is a guide how I play my anivia.
I play my anivia ALWAYS mid or solo, otherwise its a fail.
Anivia is one of the hardest champions to farm with until you have a nice amount of mana regen that gives you the chance to use your abilities to farm, because their auto-hits are pretty slow.
It's not an easy champion to play with, but one of the most usefull champions in all game.
She has stun and a super vaOE damage ulti.
Enjoy it.

Pros:
- Nice range stun.
- Huge amounts of aOE damage
- Ultimate with almost no cooldown
- Never dies at the first time
- Can engage a fight

Cons:
- Really squishy
- Too vulnerable when egged
- Mana dependent
- Dificult to play early game

I use my magic penetration marks, as usual in any nuker, my potency glyphs and my potency quints too.
You must be wondering why I use my dodge seals in anivia. First of all I dont agree with the full use of ap runes, you should use your runes to give you the oportunity to get abilities that you won't get on your game build.
I pick dodge, because I think that even if you only dodge a single atack from their ad carry in the whole game, you're winning something with the use of this runes. You will be, FOR SURE, one of the enemies main targets late game, and with their ad carries eyes on you, you must be able to atleast get dodgy from some hits.

My Masteries are the normal masteries for a caster 9/21.

I alaways start with the doran's ring, cause of the mana regen that it gives to me at the begining, because as I already said anivia is for sure a mana dependent.
I go then for the boots to increase her movement speed. After got my boots I can buy an health potion to help her mid easier and then go for the primary build, where I incresase my mana regen to farm more easily. Then the second part of the build starts with my archangel's staff, the the rabadon's, and I usualy sell the doran's when I start building my rabadon's.
Finnaly I go for the rod of age's,it's a IMPORTANT item to buy when you're playing anivia, and I almost all the game go for the banshee's veil, the give a little more resistance to anivia late game.
You have other options like: Zonya's, deathfire grasp or even another rabadon's.

Early game I dont top any ability, I prefer to charge Q and E at the same rythm. After that I max frost bite and then flash frost, leaving the wall to the end.
It's importante using the combo Flash frost--»Frost Bite to maximize and do huge damage on your enemy.

FLASH---» It's very usefull on anivia to: run away from a gank, grab kills and to try to be in a safe position when you get egged.
IGNITE---» To finish deatroying your enemy you can use this spell.

Options:
I dont see how other spells then theese 2 can be more afective and usefull to anivia, but you can use instead of IGNITE, A GHOST or a TELEPORT too.

In conclusion, I think Anivia is first of all a very funny champion to play with, not an easy one but when you handle her properly you make huge damage on the other team.
I hope you enjoy this guide, it's not perfect but I acept sugestions to get it better.