Going from 57-60 is the second longest level grinds in the game,you dont have your powerful ascended or awakened skills yet so you cant kill quite as fast,which in turn slows down your exp gain. There are a couple different places to grind this out,however the best place i have found to grind for this stretch is at the Cron castle in Balenos. It has level 64,68,and 69 monsters and requires at least 3100 CP. If you arent at that CP then you can also grind at
- Cron Castle Entrance (2600 CP)
- Castle Patrol Route (2800 CP)
These 3 spots are usually the fastest way from 57-60. if you read our http://blackdesertmobilehelp.com/knowledge-base/leveling-basics/ guide then you know what all affects leveling. So if you use most of those items then it doesnt take too long,usually around a couple days.