Lockpicking
In order to attempt to open a target chest you must first acquire some Lockpicks. Use these on the target lock and you will attempt to break it. Depending on the complexity involved versuses your current skill you have a chance of breaking the pick altogether should you fail, so a well prepared rogue brings plenty of extras. Note that often after disabling a lock, you may still have to deal with a few Chest Traps.
Training:
Best way to train is at Sonea´s Shop in Lost City. She has 3 Chests downlocked at her shop. If a Chest key is missing you may [pm Sonea. Since it is the only good way (that a player offers) to train lockpicking on the shard i beg u to return the keys when you are done. Fastest way is to get 2 chars to do it. 1 char to lock the chest everytime and your char you wish to skill just lockpicking them.
0-30: - Buy from Tinker NPC
30-54: - lockpick yellow chest
54-83: - lockpick green chest
83-95: - lockpick red chest
95-100: - lockpick chests at prisoner champs (recall from books which are next to the red lockpicking cheast at Sonea´s shop)