Bend and break minds.
The Coercer is an evil enchanter that uses their arcane power to bend the minds of others to their will. They have strong charming abilities that allow them to take over the minds of their foes, making it so that they are also a strong pet class. They can solo quite well when charming the right creatures, although they'll often get better experience and loot while grouped. Coercers also have a line of strong buffs that improve their party like Empathetic Link that gives the target a chance to do extra mental damage when they hit, or Signet of Insight which buffs the group's power pool. Coercers can choose between using a charmed pet or focusing on buffing their party, but the trade-offs are dependent on the situation at hand. Bravado increases the attack damage of a particular target - a great ability to use on a damage dealing scout class.
Coercers have a great number of crowd control abilities, the chief of which is mesmerization. They also have plenty of things to do like power siphoning and debuffing that they can do in the midst of a fight if there aren't enough additional monsters to require significant crowd control. Many of their abilities cause plenty of threat, so it's wise to use your hate reduction abilities as often as you can to avoid being splattered by an upset opponent. Spells like Discomforting Gaze cause mental damage over time to a single target and drain power in an area of effect - very useful for intense extended fights in which you need every power point that you can get. Coercers don't do as much damage as dedicated offensive classes, so it's wise to focus on your crowd control as much as possible. As you improve, you'll get better at throwing out more damage while you keep track of your controlled creatures.
Enthrall is an amazing spell that both mesmerizes your target and makes it immune to area of effect damage. This allows you to use more of your area spells without worrying about breaking your target out of its trance. Spells like Dreadful Awe mesmerize entire groups, but it's more mana intensive and of shorter duration than your single target spells. The Coercer is a challenging class to play, but it's quite fun to essentially take charge of an entire encounter through your impressive crowd control. The buffs and debuffs that you have are just icing on the cake for this enjoyable - but devious - mage.