You as a Party Cleric should dependent on maplestory powerleveling parties for your leveling. You won't max out Holy Arrow, and this means that past your third job you'll have to use Magic Claw on monsters that can not be healed. While it might not sound cool being a level 80 Priest and hitting monsters with Magic Claw, you have so many advantages so there's no need to worry.
   When you advance at level 30, you get one skill point. You should put this point into Teleport, as even one point enables you to use the skill effectively. Next up you should max your Heal. Heal not only recovers your and your party's entire HP bar, it also gives you experience when you use it on party members.
   It depends on your wishes and prerequisites after Heal. Do you have enough maplestory powerleveling money to supply your character with MP? Such being a case, you should put five points into Invincible and max Bless. Next up you should max Invincible, Teleport and MP Eater in that order. The last points go into Holy Arrow.
If you are just starting up in Maple Story, and you don't have large amounts of Mesos to spare for MP you need to max MP Eater after Heal. You will save so much money, and while MP Eater might not sound all that impressive it makes a world of difference. If you go this route you max MP Eater after Heal, then five points into Invincible, then max Bless, Invincible and Teleport. As with the other route you put the last points into Holy Arrow.
   We would recommend maxing MP Eater once Heal is maxed, or at least put a few points in it. This really depends on your characters bank account.
If you choose to go with one of these routes you will have a very strong maplestory powerleveling Party Cleric, one that will have no problems finding parties to level in after Bless is maxed. In the third job it's necessary to party to level, so people who choose to go solo in the second job miss out once they see that partying is necessary for a Priest.
Now it is the time for us to talk about Solo Cleric.
Solo Clerics are clerics who train by themselves, rather than in parties. This is a possibility, but why someone would want to create a Cleric for solo playing. After becoming a Priest at level 70, you'll have no choice but to party, so it seems that if you want a character with strong skills and spells you should rather choose a different job.