This guide now supports CDR tank Alistar and AP Alistar.
Most people prefer AP Alistar because Alistar's abilities are all AP based however depending on the team you have each build is beneficial in its own way.

CDR TANK Alistar

Pros

[*] High survivability mid game through late game
[*] Max CDR to utilize Alistar's CC ability to its maximum
[*] Easy to manipulate battles
[*] Great ability to chase/escape

Cons

[*] Easily killed early game
[*] Low damage output
[*] Not that great at farming early game
[*] Dependent on team for damage output

AP Alistar

Pros

[*] Semi-high damage output
[*] Utilizes Alistar's passive
[*] Good amount of CDR to keep Alistar a low CD champ
[*] Utilizes Alistar's AP scaled abilities

Cons

[*] Not great fighting solo
[*] Bad early game mana regen
[*] Bad early game farming

Recommended

Exhaust

is a great skill during team fights, getting out of fights, and chasing a enemy down for a fight.
[*] During team fights you should use exhaust on the carries and the high damage output champions even if they're not the focus
[*] When running away use exhaust on the champion if they're catching up to you, however if its a group chasing you exhaust the one that is able to kill you the fastest
[*] If you're chasing down a enemy and have teammates with you exhaust the runner and headbutt them towards your teammates (unless they have really low hp)

Flash

is one of the greatest summoner spells there is. Useful in many different situations chasing, ganking, escaping, and singling out one enemy to kill.
[*] When chasing down a enemy it will depend on how far they are roughly the most they can be away is around 1000 range ( this distance only works if you have exhaust ready)
if they are further than this don't bother chasing.
[*] When ganking you can flash onto the field and headbutt them before they get away giving your team the chance to kill them quickly while you disable their ability to escape.
[*] Using flash to escape is simply easy flash into the jungle or to the direction of your base/turret.
[*] You can also use flash to quickly get behind the enemy and headbutt them to your teammates direction for a quick kill.

Viable Spells

Ignite is a great skill throughout the game however I don't think its not the greatest skill Alistar could have
Teleport is useful to get to team fights or to help gank if your team has wards up. Sometimes it can be used as a escape method too.

Utilities are very important to Alistar and are very helpful, that is why 21 points are in it I don't think I need to explain it.

9 Points in offense to get the 15% magic pen and 3% CDR works for both builds because Alistars skills are all magic damage so it'll serve as a boost in damage.

Really dont know what do write here so ill just explain what each item contributes.

CDR TANK ALISTAR

[*] Chalice of Harmony provides incredible mp regen rate and a little early game magic resist.

[*] Boots of Swiftness provides speed for chasing and escaping some people buy boots of mobility but I don't think it would be as effective.

[*] Frozen Heart 20% CDR 99 Armor 500 MP and -20% attack speed on enemies what more is there to explain.

[*] Shurelya's Reverie 15% CDR, extra hp/mp regen, great chasing/escaping activ

[*] Force of Nature Provides great amount of magic resist, incredible HP regen, and more movement speed.

** Force of Nature is bought before finishing the Frozen Heart and the Shurelya's Reverie to survive better ( running/chasing, hp regen, magic resist)
** Philosopher's Stone can be bought before the Glacial Shround

By the time you get the 5 Core Items the game should be wrapping up but if its not
here are some items to consider:

Aegis of the Legion If your teammates don't have it already you can get this nice reistance and a great aura.

Banshee Veil if for some odd reason people are CCing you this is pretty helpful. Usually you wont need it though.

Abyssal Scepter AP, magic resist, aura magic pen

AP ALISTAR

Doran's Ring provides cheap ap, mp regen, and hp at the beginning of the round to survive a little better. Will be sold later that is your judgement depending on your situation you might need to sell it for money to finish off a item or if your having no money issues you can keep it till you have to sell it to make room.
Kage's Lucky Pick gives a steady gold income and some ap which will not be made into Deathfire Grasp at the end to keep the gold coming in.
Tear of Goddess provides mana and mp regen. Get it early as possible because you need to get the bonus 1000 mana bonus ASAP. Will be turned into Archangels staff

Your text to link here...Sorcerer's Shoes helps with Alistar's damage
Archangels Staff provides decent mana regen, and decent amount of AP
Rabadon's Deathcap is a must have AP item providing a immense boost in AP
Void Staff 40% magic pen stacks with masteries 15% magic pen capping at 49%
Finally the last item Deathfire grasp providing AP, CDR, and a awesome passive that deals 42.5% of the targets current hp

By the time you get the 5 Core Items the game should be wrapping up but if its not
here are some items to consider:

Abyssal Scepter AP, magic resist, aura magic pen


Banshee Veil if for some odd reason people are CCing you this is pretty helpful. Usually you wont need it though.

Being Chased:

Single Chaser
[*] Use flash if on cool down -
[*] [*] headbutt them when they get close enough (pulverize if you have the hp to take a hit)
[*] Use Shurelya's Reverie active if you have
[*] Exhaust

Group Chasers
[*] If they're creeping up on you try to headbutting closest chaser and pulverizing
[*] [*] If they are still there use exhuast/flash to ensure safety (exhuast closest)

Fighting

One-on-One
[*] Try not to engage the enemy alone Alistar's damage output isn't great with this build
[*] If you're at your turret headbutt the enemy toward it and pulverize before that can leave. If you want the kill ult/exhaust to get the kill.

Group fight
[*] If you have all the items in the build don't be afraid to charge into the middle of the enemies and pulverize and headbutt the focus toward your teammates for them to kill, don't be afraid to use ult it'll help with damage output and allow you to control the battle much longer and keep you alive.
[*] If the fight is in the jungle it is a good idea to headbutt the enemy into the walls of the jungle
[*] Always spam E when possible
[*] Don't be afraid to go near enemy turrets with the full build to stop a enemy from escaping.

Ganking
[*] As the CC champ you should start the gank
[*] [*] Top/Bot lane ganking you should start with waiting for the opponent to line up with you or if they pass you to your side of the map ( depending on which side your spawn is on) Start with the headbutt into a wall and then the rest of your team should be on the move to attack pulverize before they can escape and the gank should be successful.
[*] [*] Ganking mid basically it depends on where your teammate is if they are on the opposite side of the lane (I am talking about the bushes) headbutt them towards the bush and then pulverize before they can escape
[*] [*] [*] If they're near your tower headbutt them into the tower and pulverize

Surviving Ganks
[*] I don't know who ganks a Alistar but if people are mia make sure you have enough mana for pulverize headbutt and your ult.

Laning
[*] Do not solo a lane this build leaves Alistar in a low damage output state throughout the game.
[*] Lane with high dmg output champion to take advantage of Alistars ability to CC and get kills/assist

Combos

W+Q combo
The headbutt pulverize combo is an awesome attack.
Using it to the full potential doesn't require much skill just good judgement. Headbutt the target into/near allies or turrets or both and pulverize before they can escape. So after you headbutt they will be stationary for about 1 sec so during this time approach the target and pulverize when they should be able to move. This works best with turrets early game however late game try to have allies to do the damage.

Q+W combo
Pulverize and headbutt combo is usually used to prevent an enemy from escaping
Again not much skill just good judgment when you're chasing someone and they come into the range of pulverize you can pulverize run in front of the direction they're headed and headbutt them into your allies to kill.

These two combos also work well with the recommended summoner spells Flash and Exhaust.

for the W+Q combo flash to the side of which you need to headbutt from first and then combo to prevent them from possibly escaping(they have a lot of hp) you can exhaust.

for the Q+W combo flash to be in range of the pulverize and Q+W if they have enough hp to escape exhaust to let teammates and yourself to hit them longer and get the kill.

Protection

Team carry is being chased
Headbutt them if they're going to catch up or be able to attack.
Pulverize if group of people (if they can catch up or attack)

Team fights
[*] If teammates are being focused
[*] [*] Headbutt the high damage output hitting them or pulverize if they're in range
[*] [*] Exhaust the enemy AD/DPS champ to keep teammates alive (70% attack reduction)
[*] Pulverize and headbutt the focus then ult
[*] Spam E whenever you can (heals teammates also keeps tramble active)

Job

Early game
[*] Do not use abilities on minions early game (will waste mana and will be oom when you need to attack the enemy)
[*] If you are laning with someone that doesn't have high damage output do not push to the enemy turret until the enemy/enemies are dead.
[*] Try not to do 1v2 laning, however 1v1 laning is possible.

Mid game
[*] If your team has started to leave their lanes to help other lanes you can help them also OR keep all lanes at mid or beyond never let lanes pass the mid point or possibility of backdoor is high.

Late game
[*] Push with your team
[*] Fight in ALL team fights don't stray away to push a lane on your own or attempt to backdoor by yourself (unless the turret has extremely low hp and minions are getting close to it.
[*] Continue to keep lanes at mid or beyond unless team fight is about to take place.

Try out this build tell me what you think if you have suggestions leave a comment in the section below.

Also i have no idea how well the runes actually work because I have no IP, I was actually using corki runes. Id appreciate it if someone tried the build out the way it I listed it in this guide and tell me if something about it needs tweaking.

Oh and any tips on how to make the guide better would be nice.

Check back for updates because this build has not been fully tested yet.

v.02
-SWITCHED ITEM ORDER OF
--FORCE OF NATURE
--FROZEN HEART
--SHURELYA'S REVERIE

v.03
-ADDED CHAPTER
--SITUATIONAL ITEM PURCHASE/ SKILL SEQUENCE
-ADDED CONTENT TO
--INTRODUCTION
--GAME PLAY SITUATIONAL ACTION

v.04
-GUIDE REVAMP
--Added AP BUILD
--CHANGED
---INTRO
---PROS/CONS
---SUMMONER SPELLS
---MASTERIES
---ITEMS

v.05
-REMOVED
--SITUATIONAL ITEMS/SKILL SEQUENCE
-ADDED
--ALISTAR NEED TO KNOW PLAYS
-CHANGED
--AP ITEM BUILD
---REMOVED 2ND DORAN'S RING
---MOVED FIENDISH CODEX TO LATE GAME

v.06
-REMOVED
--WILLS OF ANCIENT FROM BUILD
-ADDED
--VOID STAFF