Looking at other people’s models, playing with them, looking at their code and generally messing with them is a good way to improve your NetLogo programming skills (once you have a basic understanding).  Here is a partial list of collections of NetLogoModels.

• NetLogo Model Library (selected and checked by the NetLogo team): http://ccl.northwestern.edu/netlogo/models
• NetLogo User Community Contributed Models (not checked): http://ccl.northwestern.edu/netlogo/models/community
• Modelling Commons: http://modelingcommons.org
• OpenABM (Includes NetLogo models as well as other kinds): http://ccl.northwestern.edu/netlogo/models/community
• A list of models described in the book “Complex Adaptive Systems”: http://vserver1.cscs.lsa.umich.edu/complexadaptivesystems
• 5 models to play with resulting from CPM papers/talks: http://cfpm.org/models.html
• Example models from the previous “Introduction to Social Simulation” course: http://cfpm.org/ISS/models/