all the guides I've seen Anivia I did not like, especially since I have not been familiar with what they say, first of all if you're a rookie with Anivia, this is not your guide, as I show here a guide which are a murderer (as leblanc) and if you can not use the Q correctly, you're dead, well, let's start.

Pros:
If your team need an assasin, you are perfect with the E
Range
Have 2 lifes ( the egg )
2 AoE skills
stun
slow skill
the trololo wall

Cons:
squishy
have 300 of movement speed ( slow )
if you dont are feeded , you are useless
you need practice

Full ap , except the red , obviously than are of Magic penetration , you are starting with 60 ap approximately ( sorry , the news masteries fu** my build , before are 50 ... , oh , forget it , this is better ), with this, at level 2, you'll be removing about half of his life if he is a mage, other characters, perhaps the 2 / 5, so Ryze ... prepare your an**

I do 9/0/21 , getting 10% magic penetration , mana per level and mana regen. , more exp. per kill and farming, 2 gold per sec. and 10% cooldown reduction for the spells ( ignite and flash ) and 10% also in skills

In lvl 1 get the Q for a leash in blue, in level 2 , the E is your new god , just take the W in lvl 10

everyone uses flash to escape, I use it to kill; Q ( if u stun him ) + flash + R + E + ignite is a kill ( just do it if he/she has a half of him life ) u are anivia , no talon lvl 18 full build

I always choice anivia if im going mid , so , if of the other side is going : ( karthus , ryze, teemo ( be carefull in lvl 1 ) or kog ) take amplifying tome with a potion of life , go B , and buy a mejai's soulstealer and ( if u can ) 1-2-3 potions of life and 1-2 of mana ( always one more of life )
But if ( kassadin , cassiopeia ( isn't so hard ), malzahar or vladimir ) is going to mid , you need 2 doran ring , boots and mana , buy catalyst and after the mejai's soulstealer

Remember , this guide only works when u are going to mid.
Do a leash in blue with the Q if u have a jungler , if u dont have doran , wait to lvl 2 for more mana , in lvl 2 , ( Ryze is your enemy now in mid )
get the half life of him life with the combination Q + E ( remember than this guide is of assasin anivia , so try it of hit 2 times with the Q ( the Q do 2 hit if u slow and after you do explode the ice ball behind him ) if you do it , you are taking maybe the 3/5 of him life ( poor ryze )
* a tip with ryze , let than he catch you and do your combination Q + E in their face , and after you are seeing whoever did more damage ;)

In team fight , you can do two things , or wait than the tank start to the fight , or take the life of the carry ( caitlyn for example , so easy for kill with Q + E + R + W ( and ignite if you are not feeded ) ) and go Back with your team.
If you choice than the tank start the fight , try to stun the more champions than you can , so wait for use your Q , let than your R slow all the other team ( in special the carry dps ) and hit with your E , all the time ( stay with your team , they need your R ) and when they are trying escaping , do your W and do an ace or go fast to push mid , if you lose the team fight , try to stay away and save your team with your W ( or get a kill with a 2-3-4-5 vs 1-2 ).
I never do the W before the fight for a 1vs5 ( except when they are feeded ) because you are trying do an ace.

This is my first guide in mobafire , im pro with Anivia ( always 14-2-5 ) so i know how play with him , the wall is just practice and same with the Q , good luck guys and have fun playing LoL is the most important , bye