I know for some people, the Liadri fight was easy. However, I was not one of those people. For me, the fight was a constant source of frustration at first.
After a few days of failed attempts on Liadri, I have found a nice build that made it simple. Most importantly though is the gear. All of the armor piece can be RARE items from the trading post. All of which can be bought very very cheaply.
Once you are set up, all you need to do is kite Liadri around the center, while applying burns to her.
The skill editor would only allow me the choose exotic or ascended, but once again, you only need to buy RARE armor pieces.
http://gw2skills.net/editor/?fVAQRArd7flsApZotCxfH8DRR8Ql5YkG2UdAkAPKePBA-ThhAwAUUCiU5Hs9HAq+TnTCAgnAAA-e