This is my first guide, so any advice and constructive criticism is appreciated!

This is strictly the build I use for ARAM.

If people like this guide and find it useful, I will consider writing more ARAM guides.

The reason I post on here is that I often go looking for builds for champions and how to build them in ARAM, but there aren't many ARAM guides about.

Also, I thoroughly enjoy playing Alistar in ARAM because he is incredibly strong, especially if you're a selfless player, you will make sure your team is fed and well-protected.
With the amount of healing you end up doing through Alistar's passive ability + this rune setup and shielding with Locket of the iron solari, you'll easily do 20k+ healing during a game of Aram whilst being comfortably tanky.

By no means are the item purchasing order set in stone, feel free to change it up, but these are my personal preferences.

Now for what makes this build so fun and strong, in my opinion.

Resolve


Aftershock is my preferred keystone rune on Alistar in ARAM, simply because whenever you immobilize(read: this is the bread n' butter of Alistar) you gain a whopping 20 Armor and Magic Resist + 30% for 2.5 seconds.
After this, you explode dealing damage to everyone around you. The damage is respectable and becomes better as you gain more HP over the course of the game, but it's the armor and magic resist increase you'll love from this rune!


Font of Life is really great if you have at least one ADC or generally basic attack happy champions in your team composition.
Whenever you do your CC, that enemy will be marked, thus healing any of your teammates that attack it.
The noteworthy thing about this rune, is that your teammates will, as the game progresses, receive more and more healing from this rune because it increases based on your(Alistar's) max health.


This rune is arguably the weakest one in this rune build, but because team compositions in ARAM are random and you don't see your opponents setup until you're on the loading screen, I cannot in good conscience recommend Iron Skin nor Mirror Shell.
Having said that this is probably the weakest rune in this build, it's still quite strong - Obviously not because you get 8 armor and 8 magic resist after 10 minutes, but because the rune also increases your armor and magic resist by 5%. That's still quite strong.


Revitalize is my favorite rune in this build. For me, it revolves around this rune, Alistar's passive(read: Triumphant Roar) and Locket of the iron solari - That will be how you help your team stay alive during teamfights.
All you really need to do for it to work is to be near as many of your teammates as possible when you're fighting, so you'll heal as many as you can with Triumphant Roar and let it do the rest.
Pop Locket of the iron solari during teamfights, but don't wait until your team are low or you'll risk losing them instead, but more on that later!


Precision


Takedowns(read: Kills AND assists) will restore 12% of your missing health and grant you an additional 25 gold.
What's not to like? Triumph will often end up giving you a lot of healing during the course of a game and a bit of extra gold here and there never hurt anyone!


As a tank you simply must have some tenacity. It makes it easier to engage and escape fights. This rune paired with Mercury's Treads will do you a world of good.

There are, of course, a number of different ways to play Alistar, but regardless of whether you're incredibly aggressive as a player or more careful, just remember to always play smart; If you're dead from recklessly charging into the fray, you will be of no help to your team!

When you start getting a couple of your items you will quickly notice that you can tank a tower for a bit during the earlier stages of the game, but don't do it unless you're certain it's worth it for your team. Don't go for personal glory.

Now for explaining why this build works so well, in my opinion.

Triumphant Roar

Before I say anything else about Alistar's passive, I would be remiss if I didn't first explain how to "use" it.

1.Triumphant Roar procs when it has reached 7 stacks by killing(or being near when others kill) minions.

2.Triumphant Roar also procs when you kill or assist in killing a champion,
but it does not, however, count toward stacks - You simply get the passive activating straight away! You do however get stacks toward it when you hard crowd control an enemy champion

3.Triumphant Roar has a 3 second cooldown after it has activated
Your team will love you if you play it right. Triumphant Roar not only heals yourself when it procs, but it also heals all nearby champions for twice the amount of it.


Your team will love you if you play it right. Triumphant Roar not only heals yourself when it procs, but it also heals all nearby champions for twice the amount of it.

In order to make the best use of it, you will have to find a balance between being in the front and keeping an eye on when an enemy champion is about to die so you can quickly get close to as many of your teammates as possible to heal them. It'll take some practice, but it's worth it!

Another important point I touched upon earlier in the guide is how to use

Always use it when you and your team are engaging in a teamfight, whilst your teammates have a lot of health left.
If you use your shield early in a fight, there's a bigger chance of of absorbing a lot of damage from the high damage abilities of the enemy team, but also because it will allow your team to hopefully get the first kill of the teamfight, thus getting Triumphant Roar going with a heal to properly turn the tide of the battle!

Throw 'em around!



So how do we set the kills up for the team?
Well, there's the most used way of getting within range of an enemy champion, using W(Headbutt) to charge, instantaniously using Q(Pulverize) as you land to knock them into the air. Mistime the use of W and Q and you'll instead end up knocking the enemy away.

My favorite; Throw your snowball at an enemy champion, teleport in, use Q to knock target into the air, quickly walk behind them and use W to charge the target into your teammates for the quick and easy kill.



You'll probably, by now, have noticed that I haven't mentioned Trample(Ability: E) that much.
You might even be thinking that it's probably not that good of an ability because of it, but I assure you that it's a great ability.

It allows you to stun a target after you've reached the max stacks on Trample, by simply staying close to enemy champions.
Also, it does deal a fair amount of damage so sometimes it can help you to secure a kill if someone is looking to escape!



Last, but by no means least, we now end up looking at our ultimate ability, Unbreakable Will

When you activate this ability, you firstly remove all disables(read: crowd control) and secondly, you get a flat 75% damage reduction for 7 seconds when at rank 3!

Now for using it, you have two choices in my opinion.

1.You can choose to use it when you're dipping low on health, which isn't necessarily a bad choice. It CAN save you, but most likely you'll end up dying anyway without having used the full duration of the ability

2.You can use it before you dip below 40-50% hp or even just as you've engaged and you find yourself in the midst of the enemy team to ensure your teammates have time to come near and back you up. This is my preferred choice.

If you've made it this far into the guide then you're ready for when you randomly receive Alistar and you know what to do!

If there's something you feel I haven't covered or if you simply have a question, feel free to leave a comment and I'll try to answer as well as I can.


Thank you for reading my first guide, I hope you enjoyed it!