Khenarthi's Wrath
This build is what I use on my Sorcerers in Cyrodiil, Imperial City, and Battle Grounds. For BGs I recommend using Charged Atronach instead of Absorption Field. Mag sustain can be difficult in extended fights with the melee setup, as such it can be good to use Dark Conversion instead of streak for beginners.
This build is meant to work solo or in groups, while not designed for 1vX you can generally stand up to 2-3 enemies solo. If you prefer to take risks, you can use Divines for the Armour traits and the Thief Mundus to up your Critical Damage.
Skill Guide
Skill 1: Cast Haunting Curse on your target as your first attack, only cast again after both explosions.
Skill 2: Melee, cast Crystal Fragments when it procs. Ranged, cast Crushing Shock when an enemy is channeling to interrupt them (can be used as an alternate spammable, just remember to keep Mage's Wrath up on your target at all times)
Skill 3: Cast Mage's Wrath as your spammable
Skill 4: Cast Twilight Matriarch when you or an ally needs healing
Skill 5: Cast Streak as needed to stun enemies for AoE damage from yourself or allies. Alternate, if you are having difficulty with sustain or there's already a few sorcs with streak in your group, swap in Dark Conversion to help with Mag sustain and Healing, as well as ensuring that you can proc the Exploitation passive and get Minor Prophecy for you and your group.
Ultimate: Cast Absorption Field on flags to stun NPCs and silence Enemy Players on the flag. Can also be used to help protect players on rams. or to try to stop tower humpers and ball groups. Absorption Field is used instead of Suppression Field as the extra damage to enemy NPCs is less valuable than extra healing for you and your allies. If you find your enemy players are particularly dense and they are willing to stand in your bubble of silence Suppression Field can be used.