Welcome to my Annie guide!
Annie is an underrated, but very powerful combo champion (much like Anivia, Ryze, Veigar).
She has great burst and survivability, a cute voice, and one badass bear, Tibbers. :)
Enjoy my guide~

Runes
I use:
x9
x9
x9
x3

When it comes down to raw damage, nothing can really beat Magic Pen. With 9 of these and Sorcerer's Shoes, you'll basically be eating through the average Magic Resistance of 30 easily. For tanks, you'll be relying on Archaic Knowledge .
C'mon. Epic mana regen. Annie could get away with using something else here; flat health, dodge, etc. But if you want to use your Incinerate to harass or charge your stun early game, then you need these.
Flat CDR. Between these and masteries, Disintegrate has nearly half a second taken off of it's CD, which is important for early game farming. Not to mention, in the heat of a team fight, or when you're ganked, you'll need any CDR you can get. Annie is very combo oriented. These are important.
I've recently changed to these. While it's true that Magic Pen technically leads to more damage, you have about 30 Magic Pen with your marks and masteries. And early game, the AP is more noticeable than Magic Pen. With 3 Greater Quintessence of Ability Power plus Doran's Ring and Archmage's Savvy you'll have 31 AP at level 1. Disintegrate has an AP ratio of .6, so when you're farming at level 1, you can kill any minion with less than ~105-108 HP, thanks to your Magic Pen.

Masteries
9/0/21. More or less standard. However, I do take 1 point in Good Hands because I use neither Ghost nor Teleport on Annie. I recommend that you use whatever Masteries and Summoner Spells you are comfortable with. My guide is simply that; a guide, you don't have to follow it 100%!

Summoner Spells
For Summoner Spells I take Ignite and Flash. Like I said, these are more or less about preference, but I will explain my choices here. Ignite is useful to nullify healing, and for that extra bit of damage when you're taking that First Blood, or for when Annie's combo leaves an enemy champion with <100 health. Flash is extremely useful on Annie for two reasons. 1) Escaping. Duh. 2) Setting up your Combo. Flash in with Pyromania and Summon: Tibbers and let 'em have it while they're stunned.

R->Q->W->E.

Start off with a rank in Disintegrate; you'll be using this to farm. Try and get the middle lane; it is very important that Annie gets Summon: Tibbers ASAP.
While you're laning, make sure that you only last hit minions with Disintegrate until you're ready to kill an enemy champion. For multiple reasons:
-Annie gets the full mana cost back if her target dies.
-Gold, Gold, Gold.
-The enemy will think you're docile.

If you have Greater Seal of Scaling Mana Regeneration and a Doran's Ring, then feel free to harass with Incinerate between levels 1-5. Make sure to try and hit the Caster Creeps while doing so, however. However, no matter how tempting it is, don't waste your Ignite (if you have taken it as one of your spells) and do not hit the enemy champion with Disintegrate unless you are trying to secure a kill. When you hit level 6, you want to have enough mana to do your full combo. At 6 you should have 3 ranks in Disintegrate, 2 ranks in Incinerate and 1 rank in Molten Shield (This is optional; however, I get one rank in Molten Shield at level 4 because 1) Armor and Magic Res, and 2) It helps charge your passive's stun ;) )
Now, if you're in mid, it's time to punish that enemy champion. If it's a squishy (eg, Karthus, Ryze, Ashe, etc, etc) flash over/quietly edge closer, and BAM! Full Combo. (R->Q->W->Ignite). Try and use Q before W since it has the shorter CD, unless the enemy has Flash-- in which case, it may be smarter to Incinerate first, so they have a smaller chance of escaping/surviving.
Annie dominates mid. The only champions that can really give you trouble are 1) a good Kennen =_= and 2) a really good Teemo. Even Vladimir won't stand up to your burst at level 6, though a good Vlad may find it easier to escape than most champions with Sanguine Pool and Flash.
Now remember, if you're destroying the champion in Mid, don't push the tower. Let your minions do it. Annie doesn't kill towers. (Though Tibbers can; feel free to have him attack towers: Alt + Right Click to control him). You don't want to leave yourself open for a gank by auto attacking the Mid tower. Instead, Move back closer to your own Tower, or go pressure Top/Bot. With your stun up, you can generally secure a kill or assist, even without using Tibbers. This makes you almost as terrifying as a fed Twitch or Evelynn, because who knows when little Annie will pop out of a bush with an angry bear!!

Generally, you want to start with Doran's Ring and a Health Potion; Annie has no mana problems because of Disintegrate, and the Mana Regen, Health, and extra AP make this item invaluable at level 1. The only alternative I recommend is Doran's Shield, and this is only if you are 110% sure that you'll be up against an AD champ in Mid. (I mean AD, not melee! Champions like Katarina and Mordekaiser deal more Magic Damage than Physical!)
Champions you might consider getting a Doran's Shield for are Pantheon, Xin Zhao, Caitlyn, Sivir, and maybe Ezreal. I would not get one for Ashe or Twisted Fate, generally.

On your first trip back, buy Sorcerer's Shoes. If you do not have enough gold, just get the basic Boots and some pots, if necessary. After Sorcerer's Shoes, you will be aiming for Rod of Ages, usually with Catalyst the Protector taking precedence over Blasting Wand. If you buy a piece of Rod of Ages, but don't have enough for the other, think about buying Amplifying Tome, since Mejai's Soulstealer is your next item.
At this point, you most likely have:





Now, for explanations. Sorcerer's Shoes > all other boots for Annie, except in certain, extremely specific situations. the Magic Pen is amazing. I usually go for Rod of Ages because the health makes you surprisingly tanky, especially with Molten Shield up, besides... the AP and Mana are quite nice as well. Mejai's Soulstealer shouldn't require an explanation. It is an amazing source of AP throughout the game, even if you can only keep up 10-12 stacks. As with any snowballing item, keeping yourself alive should be an extreme priority. Do not take risks without justifiable rewards! Don't towerdive that Master Yi that has no bounty. Don't try and save your tank that ran in to save you and a teammate from a 4 champion gank-- let him do his job! Don't try and 3v5, even if you know you can take 2 of them out. Keep up your Stacks, at all costs! (Except for the cost of the game; your team will hate you for this, and you will most likely be disappointed in yourself, as well). Because honestly, who cares if Miss Fortune gets angry and says "Gee, thx annie f4g u nub culda saved me f4g why didnt u help nub gtfo"
=_=' If you know you can't save them, don't try it. Most of the time, it only ends up in you dying as well, and losing stacks.

Mid-game is underway or Late-game has started. Get working on your Rabadon's Deathcap! Try and build Needlessly Large Rod first, but if you're forced back to base with 1200 gold, might as well get Blasting Wand first. Bang for your Buck, ya know?
Your next priority is Archangel's Staff. It doesn't really matter how you build this, but I prefer to get Tear of the Goddess first, to help get your Mana charged up faster. Usually I'm able to finish Rabadon's Deathcap and get Tear of the Goddess at the same time, but if you can't, then no sweat. Get to farming, jungling, dragoning, tower pushing, and champion killing!

End Game:







If your game goes on longer than this, or if you're exceptionally well fed - truly a possibility, then sell your Doran's Ring for a situational item of your choice.
Lich Bane, Archangel's Staff, Zhonya's Hourglass, Abyssal Mask, Banshee's Veil are all good choices.

Give it a try, Gimme a comment, and please- constructive criticism only! This is only my second MOBAfire guide. I would like to continue sharing my ideas, but only if people will take my unorthodox playing style, and give it a shot!



Thanks,

Murasaki no Tora.