Welcome to my Alistar guide.
I will be focusing on both AD enemy team centered build and AP enemy team centered build.
Rememeber that if u think i should do something with this guide, just tell me.

Pros

Extremely tanky and a great initiator with his combo
Almost never dies

Cons
Pretty squishy early game
Can die if grouped

When initiating

Use Headbutt and a quick pulverize to knock them up, while still staying where they are

When escaping

pop your ult, run like hell, try to dodge, use triumphant roar and pulverize to create some distance. remember that your heal can be precious, try to save mana by not healing, but use flash then heal, so the enemies dont bring your health down, if flash is on CD try to dodge by moving in the grass then turn, then headbutt the chaser, then pulverize then run