Hey and welcome to FF.
Fiesta is a really good game, and my first love as an MMO. Coming to which class you would like, there's
this nifty little guide written by SpeedySnail (which unfortunately does not cover tricksters) and
an equally nifty building guide written by Hessah (which also doesn't cover tricksters as they were both written before the class was introduced).
If you would like my own opinion, I think it is easy to start out and get acquainted with the game as a cleric, if only because of the ability to heal yourself. Once you get to about level 10 and understand the mechanics of the game, you can start over with whichever class catches your fancy.