I like when some ppl suggest to newbie stuff meanwhile they know shit about that themselves...
Mate, first here is short version. DONT PLAY BISHOP.
The longer version is following, aka emo crying experience and pov of one bishop; tl;dr :
At this point of the game its 90% of time literally useless char.
1) exping: At this point there are two locations which requires presence of bishop. Lair of Antharras (60+) and Blazing swamp (70+). Both cases only in aoe parties. So if you go there single-targeting (archers/small mellee groups/cdl) its useless again. Raid boss parties you can skip , you have almost no buffs and heals there are with current mechanics (jsut bug minions - agro and run and the rest shoots from bow) not needed, so nobody will really invite you. All aoe locations below 60 are usually done without bishop as well - simply its not needed (usefullness of EE/SE there is much, much, much higher than bishiops). And solo? Yep, you have one nuke but only for undead monsters. Dont worry, there are plenty of undeads in all level ranges but if you go nuke with that nuke you will realize that after 2 minutes you will rest MP for another 10 minutes. Viable combo is duo with SE for that, he will buff you empower, root mobs and recharge you.... and you will jsut kill it but with windstrike (that skil lfrom level 1) not turn undead (more MP/damage ratio). I even tried melee style solo bish but meh... you are killing mobs for eternity. If you somehow choose bishop anyway you need to find CP as fast as you can. Or in some cases good clan is enough (as a good clan i mean they invite you to parties even isntead of their more usefull (read it as SE/EE) box) even in low levels. If you deal with all this stuff another problems will appear...
2) playstyle: @MoDoy is particulary right, bishops havent reached their full potential yet. But that doesnt mean they are easy to play (read it easy to play good).. The main problem is MP. The second biggest problem is MP and third MP as well. There are few tricks how to manage that pain, i guess every bishop discover some of them by himself. If you are not carefull you burn your MP literally in seconds (it doesnt matter if pve or pvp) and after that you (and your party) are doomed.
Also, lot of peoples philosphy is simple "Always blame supports" so if something goes wrong, you are one of the first persons to blame Next, life of bishop could be tricky sometimes, you can basicly leech for long minutes but it suddenly appear some yummy situation like tank stuned, 2 ppl paralyzed, 3 ppl sleeping, one afk, two dieing and you have sooo little time to make crucial decisions what to do first, second etc...
3) equip: I dont agree bishop is low-cost char. True is you dont need ++++ weapon necessarry but what other ppl invest to oe weapon, you should invest into armors/jewells. Im starting to have nightmares about 2.0, at that point you will need 4 weapons (which 2 of them should be best possible). So lets sumarize that: +++ jewels (okay, same for all), 2 armor sets (light/robe) (best enchant possible ofc), 2 shitty weapons (MP regen and run speed runes), 2 good weapons (healing power, cast speed runes). As a cherry on top of the cake with all this shit in inventory you dont have much space in inventory cos of weight penalty so every death brings huge risk of droping items. GGWP
4) bishops destiny: get ready when you log you will recieve many pms like "come to ress me to xxx pls" meanwhile sometimes they even forget to tell you that enemies are there (so in the end this adventure will cost you some % as well )... In pvp you are one of the first targets so you die even 2,3 times before gvg is resulted... Meanwhile in pve if you are lucky you are second one to die (after tank), if not - first one to die (damn, healing causing soo much agro) and ress you will recieve is shitty compared the ress you give your party mates Dont get me wrong, i like playing bishop but its definately not for everyone, you have to be carefull about that. Oh and also im not claiming to be some pro so you can expect some flamers will tear this apaprt but w/e.
I would realyl suggest you SE/EE if you want play active healing-kind of support. Maybe more SE thanks to its versatility (even soloing is not a bigh problem and it doesnt matter if mage/melee). Good luck ingame whatever you choose.