Archers are usually good at this in  4Story. We won't go out on the limb as everyone else saying they're overpowered because most think so but they've tried balancing classes. Anyway dueling and PvP is super fun and this is where Dexterity comes in big time! The more Dex you got the less you're going to be hit and the more often you're going to deal your opponent damage. If you need 4Story Gold you can visit our site and you will find the price is very low .
 

Facing a Priest - A little bit tougher of a class to face sometimes due to all their buffs. First you will want to cast Lapiris' Blerssings about two seconds before the match starts, then I suggest using Flash Bomb arrow or Chaotic Arrow while invisible to try and knock their buffs off of them. If you get them off definitely follow up with a Snipe you're pretty much golden after that if you haven't won or if they have healed repeat the Lapiris' Blessings and hit them with your heavy damage shots.

Facing a Summoner - In personal opinion they seem like one of the easier classes to kill, but you have two things to kill. Destroy the pet first with Sharp Arrowhead then a few shots of regular shots. In this time the Summoner will be preparing to smack you down with a barrage of skills but once the pet is dead the Summoner soon falls too. Flash bomb the Summoner once the pet is dead then use the skill Snipe if that don't finish it off use regular shots it'll fall soon enough.