Links to guides in the official forum.
Mercs: http://flyff.gpotato.com/phpbb/viewtopic.php?t=808123
Blades: http://flyff.gpotato.com/phpbb/viewtopic.php?t=808133
Knights: http://flyff.gpotato.com/phpbb/viewtopic.php?t=808083
Mages/Psy/Ele: http://flyff.gpotato.com/phpbb/viewtopic.php?t=215853
Assists/BP/RM: http://flyff.gpotato.com/phpbb/viewtopic.php?t=604313
Acros/Rg/Jesters: http://flyff.gpotato.com/phpbb/viewtopic.php?t=542853
If you want to learn about good builds for mercs, go read up Eph_'s guide, I would say it's really good for blade-to-bes. And as you can see, the moderators in Mercs put in more enough getting the section tidy. I think this was why I became a blade. -_-
You will realise a lot of the guides neglect to mention about the skills we should learn/utilise as the class we are. I suppose if there are any questions, you can ask about the guild for help on what you should learn and what you shouldn't.
One more link that really helped me: FlyffFansite. I referred to there when I need quests info or equipment info or npc locations.
Fansite: http://www.flyfffansite.com/Equipment/equipment_set.htm
Worldmap: http://members.home.nl/gerlio/worldmap.jpg
A couple of elements for mobs are wrong, for eg: Boos. I elemented my weapons with lightning thinking I can train there instead of Carrierbombs. Guess who turned out to be earth instead of water element. WTT. I still love the worldmap though. It's accompanied my training a lot whenever I'm done with a mob.
Updated: 19th April 07