It is relatively easy to master the battle strategy with the Assassin. Usually a player sets to reach a certain goal and pick the target as fast as possible. For an Assassin, the goal is not difficult to reach since the enemies are unable to see a player with the invisible ability. That means choosing the right enemy is extremely important.
When it comes to choosing weapons, a player prefers to go with dual daggers and a bow. It is noticeable to differ in the damage of a single dagger and the damage of wielding two of them at the same time. The bow is especially for pulling mobs. With one bow, A player will not be forced to run into a group of them (this is especially useful when a player is pulling a mob around other aggressives of a different type).
Once a player chooses a weapon, he is ready to go for targets. In PvE, a player will cooperate with others or fight solo. In solo combat, killing a mob at one or two levels is much easier; however it gets difficult as killing mobs at higher level above the player.