(if you come from IAH games, monk is acylote, and priest is oracle :P)
Acolyte/Priest: Eleven Tips that hopefully will help you to start off.
First tip, get diffusion cannon just at lv2, you'll replace it as soon as you become a priest.
second tip:get slow heal lv5, only if you are planning to improve it to lvl 10, otherwise, isnt as effective to invest points in here, despite the fact that its a team HoT (healing over time) spell, from lvl 4 and onwards.
thrid tip:get focus lv 5 ( and select the NO HELMETS option in your settings if you get bored of the cat head )
fourth tip: dont get either the meteor or the lightning skill as a magician, you wont use them at all later on.
fifth tip:spam the X button, dont hold it down but reapetly press it. Your ASPD (attack speed) will aid you in here, the more aspd you have, the more spheres per second you can throw, hence, the more dmg you can do.
sixth tip:as a priest, the double shot skill doesnt stack with diffusion cannon, so you'll replace diffusion with double shot. the former splits you attack into three spheres that hit for 72% of your matk, whereas the latter shots two spheres at a wider range, each hits for 1xx% of your matk, and has a mini aoe effect that hits 2 monsters.
seventh tip:get rain of fire, it does nice damage AND its the only skill to make booses go into groggy for monks
eighth tip: get instant heal to lvl 5, cure to lvl 1 if you only want to pve or higher if you want to pvp, and resurrection to lvl 1 only, detection is only usefull for pvping. get casting acceleration to lvl 5. Sanctuary is a waste of points, as well as wide heal. If you think its worthy, you can get wide heal to lvl5, and combo it with casting acceleration, so as to make the cast last only 0.2 secs ( my advice is to not get this skill, and get HP Restore as a priest instead, its far more useful because of its healing range, healing amount, and party HoT. )
ninth tip: get as much VIT/HLT from equips as possible, this stat will skyrocket your hp for you to tank hits and kill/buff meanwhile, else, you can go evade/health priest. One point in INT isnt nearly as good as one point in HLT, you matk is mainly provided by you weap and its refine, other than your int, so you'll find extra hp way more profitable.
tenth tip: try to get the 10k combo medal asap. its godly. you can live with the 5k one without a problem, but u'll miss those extra points.
eleventh tip: get the def or hp jewelry, as it will improve your survival. but, if you think you can handle things better than the average, you can always go with the matk ones, that will make a slight difference in your overall dmg.