I've done all of Magatia's quests. All of them are hard to complete since I'm just a priest which isn't an offensive type job. Some of the quest I had to read the forums and guides for certain websites. One of the website I found had brilliant guides for all Maple Story quest. It's guides are straight to the point and easy to understand.
Here's the link to the website for Maple Story. Click here.
There's more game guide in that website. It's good to have one game guide website which is updated quick and accurate.