This study guide should provide you with a solid foundation for creating your own models. It is designed to be done in conjunction with Learning Lab 6, which provides a detailed lab for starting with an idea and ending up with a completed original model, although if you are new to NetLogo, you are probably better offer completing the earlier Learning Labs first as Lab 6 is more advanced.
The NetLogo User’s Manual provides a lot of good resources for learning NetLogo. These tutorials build upon many of them, drawing from the Programming Guide, and expanding on important concepts.