If your just starting in Spigot Plugin Development, you will want to learn the Api. So go over to the wiki and look at all the methods, events etc, and try learn use those by learning what each do. What i'm meaning is creating small plugins that utilize each class. meaning you will learn along the way how they act in game. This way when you come to creating things, you will know the best ways to do things, and how to do things since you would've learned each aspect of the Spigot Api Classes.