Basically to level acolyte quickly, put every single available point into int. Then, once you have heal (at any level) head to the prisons via speaking with Anne the Stylist in the job change building and trying to take her money. Prisons is a KS zone, so just use heal on the zombies there via Shift+click ( or type /ns and then you won't need to hold shift to use heal as an attack on the zombies). Just stay in the prisons and keep heal bombing the Zombies till you are able to change your job into priest or monk (I recommend changing at 50 as an acolyte, you definately will regret changing even at job 49 whether you follow monk or priest)
Priest is pretty easy to level up once you change as you can stay in Prison and keep heal bombing until you have enough skill points to get Turn Undead. Unless you have gears to make it cast in a reasonable time, and/or have a tank with you, Magnus Exorcismus is tough to level with as most mobs will have been killed before it has finished casting, or whuile casting a monster will spawn next to you and hit you, thus canceling the cast. With a Turn Undead build, you will need int and luck to make Turn Undead more successful. You will want to change stats around to make int and luk pretty close to each, with a little more int than luck to increae you heal amount and to increase damage against undead property monster when Turn Undead fails. You wouldn't want max int and no luk. This is because the formula for Turn Undead adds int and luk together.
Turn Undead's formula is:
[(20*Skill Lvl) + Luk + Int + Base Lvl + (1 - TargetHP/TargetMaxHP) * 200]/1000% (with a max of 70%) chance to succeed.
So lets say you had 99 points in int and none in luk. Your turn undead chance wouldnt be as great say if you changed your stats to look like 60 int and 60 luk (this is just an example).
The downside to Turn Undead is its 3 second cool down and the fact that you cant handle large mobs as well as a Magnus Exorcismus build with a decent cast time. But if you can afford the dex gears to get Magnus' 15 sec cast time to a more reasonable amount, I would recommend a Magnus build over a Turn Undead for leveling in Prison.
This is my skill build for Acolyte turning into a priest:
Heal 10
Divine Protection 5
Increase Agility 10
Blessing 10
Ruwatch 1
Teleport 2
Warp Portal 4
Pnuema 1
Aqua Benedicta 1
Cure 1
Angelus 3
Decrease Agility 1
My Priest skill build for Turn Undead:
Status Recovery 1
Increase SP Recovery 4
Resurrection 1
Lex Divinia 3
Turn Undead 10
Impostio Manus 3
Aspersio 4
Sanctuary 3
Safety Wall 8
Kyrie Eleison 4
Magnificat 3
Gloria 5
My Priest build for Magnus Exorcismus:
Status Recovery 1
Increase SP Recovery 4
Resurrection 1
Lex Divinia 5
Lex Aeterna 1
Impostio Manus 3
Aspersio 4
Sanctuary 7
Safety Wall 1
Turn Undead 3
Magnus Exorcismus 10
Magnificant 3
With this build there is 6 skill points remaining which you can dump into whatever skills that you may want.