A build based on AP and mainly magic penetration. Pretty squishy but can kill a tank alone in mid game.
It is a build made for a good starting game.
Tear of the godess makes your mana reserve going larger at early game.
As annie is a spell spammer with her first spell, your mana will grow up easyly.
Sorcerer's shoes are necessary for this magic penetration based build.
As you will be pretty fragile, the haunting guise, and his spell vamp will quicly becamo handy.
Jungling will never be so usefull in mid game.
The void staff will change everything in the game. Once you'll have it, you'll be able to face a tank without fear and any melee hero will back when you'll throw you're disitegrate spell.
As it won't be efficient until end game, upgrading you're tear into an archangel staff will give a nice boost of AP. Try not to buy it too early, killing one or two heroes before buying it and come back again with a crazy boost will be usefull.
The rylai's staff is one of the best item in the game for annie, as tibbers will slow everybody close to him. you're AoE spell will quicly become fearsome with it.
I used to buy it earlier, but as for the archangel staff, the surprise is better in end game. Again a nice boost of AP and mainly a big change in annie's playstyle.
Zhonia's ring is the last item to buy, but generally, if you buy it (even if you'll become an enraged beast) it means the game is nearly over... for you.
Spells must be taken logcally. You need your damaging spells to be up quickly, and you must start with desintegrate in order to be able to finish mobs easyly, without mana cost and with gold reward.
Molten shield MUST be taken at level 4, not really to protect you but mainly to charge your stun as it cost few mana points.
Tibbers must be taken at level 6/11/16, he is your best weapon and must show up the more often it's possible.
Always try to charge your stun before launching tibbers, or in a 1v1 fight, stun him with desintegrate, launch tibbers on him and then incinerate him.
Many combos are possible with annie's stun.
Runes are like this :
9*Magic Penetration Marks (do i must explain ? ^^)
8*Dodge Seals (giving 6% dode, which will give you some survivability)
1*Ability power Seal (completing you AP rune's reserve to 30 at lvl 18)
9*AP/lvl glyphs (guaranteeing more AP for end game)
3*AP quintessence (to start with 17 AP, which is appreciable)
Summoner's spells are Flash and Teleport.
Flash is necessary, finishing running ennemies with desintegrate becomes MUCH easier.
Teleport is vital on the 5x5 map, in order to come back real quick in early game and not losing any xp point, which is very important with annie, and also in mid and end game to always bring you're crazy burst damage to team fights at the good moment.
Teleport will be replaced by heal on the 3x3 map, in order to survive more in early game and to give allies a hand when pushing. If heal is taken, change mastery point in teleport for one point in Good Hands, because you must be realistic : in a high level game, you WILL die.
Remember that even if Annie is really squishy, you can always survive using your very good range and your crazy stun wisely.
Try always to be behind your minions to avoid many abilities and don't hesitate to back when you don't have advantage.
Try, if you're not mid lane (best place for her) to never be alone. 2v1 fights will rarely be forgiving.
Now, be prepared to hurt reaaal bad and to have hard time surviving. ;)