2Moons New Guide for PvP
First of all, do not even try to PvP when you are below level 36, you will just not do well. However, mages gets good at PvP once they obtain their level 36 spells. If you are going for a PvP build, you should opt for a maxed Seize Nimbus at the loss of a couple elemental mastery levels.
Also you should do a max heal stat build, meaning reach the spirit and strength requirement for your weapon and put rest of the points into heal. At level 92+, the obvious skills to use for PvP are the high end ones. The lightning series works best due to their stackable attack damage bonus.
But at mid and low levels in 2Moons, there are some controversy as to whether the level 36 or level 51 spells works better in PvP. IMO, you need to know how to use both in order to be good at PvP. Level 36 spells should be your primary attack skills, they do have a long initial casting time, but it will be well worth the time once you get the chain of skill spam started.