I'm having Trouble With Fiesta Online.?

Alright, when I launch Fiesta, the game starts up as it should, but when I do strat to play the game. There SERIOUS, I MEAN SERIOUS lag, almost of the brink of freezing. Okay so what do you guys do when you play OTHER MMORPGs. Or if do play Fiesta, tell me what you did if at a time you had these same problems.