"Predicting the future of an individual is difficult. The stars know much but guard their knowledge jealously."
World Luck quests are divided into Tyara's Blessing and Solarien's Gift quests. Both can be obtained every day from Henry in Freedom Harbor or by accessing the daily event schedule by pressing the "U" key.
Both of those quests are the same for everyone and require players to complete other dailies, events or even instances. After completing the mission that you got from World Luck you can return the quest to Norchardens who is located in Alameda Park in Freedom Harbor (57 10, 0 57) to receive a good amount of experience and if you're lucky, more experience and the title "Star of Luck".
Personal Luck has the same rule as World Luck quests beside that the task to complete is given randomly to each person. Of course a few people may get the same quest to complete for Personal Luck - they can repeat among players, there just isn't a set quest for everyone to do like in the other Luck quests. Personal Luck has a maximum of 3 times per day, if you have a special Lucky Top, you can trash or retry a Personal Luck quest you failed at no expense of the limit.