Alistar is a great support with hes Triumphant Roar and headbutt, with Alistar u will have to pulverize the enemy then run behind them and knock him towards ur allies. NEVER knock them towards their base and help ur enemy escape. In the beginning buy one Meki Pandent and 2 health pots, the meki pandent with help out with ur mana problems. The first trip back u should buy a chalice and boots. Inerventing locket is self explanatory. Shurelya's Reverie and Randuin's Omen has a pretty good combo for escaping a failed gank or ur being ganked this works for u and ur whole team(as long as they stick with u)the cooldown reduction from both items are nice because that just means more heal and more pulverize. Aegis of the Legion's aura helps alot as well.

Summoner spells
Rally: in team fights or ur kicking the turrets *** nice boost
Flash: always a good spell to escape initiate and chase
Options,
Exhaust slowing and blinding their dps is nice
Ghost chase those bastards down and give them to ur team.

Item options,
Heart of Gold.
Banshee's veil
If u want Ad take Atma's Impaler.
QuickSilver Sash is good if you are having troubles with disables.
Thronmail



In early game try to push the tower as much as u can but never push to far if there is a MIA alistar's base movement is 300 so he cant really run. If u want to scare them bak with head butt like just hit them with if u can but be careful of ur mana.

Mid game ur gonna start really pushing these towers just run up with a wave and pop ur ulti stay as long as possible, if there is a team fight run in headbutt there tank out and then pulverize. DO NOT FORGET TO HEAL UR TEAM, that is very important. By this point u should have the innerventing locket and everyting before that.

Late game if ur team is not doing well use ur Randuin's Omen and Shurelya's Reverie combo to escape but Randuin's omen could be used in battle as well do the lower AS the enemy gets. It is all about team fights here just do the best u can and u will see the results,
Good luck and have fun.