I've found it to be helpful to take a look at large open-source Django projects and take note of how that project does it. Django's site has a good list of open-source projects:
http://code.djangoproject.com/wiki/DjangoResources#Open-SourceDjangoprojects
As does Google (although most of these are smaller add-in template tags and Middleware:
http://code.google.com/hosting/search?q=label:django
Of course, just because one project does it one way does not mean that that way is The Right Way (or The Wrong Way). Some of those projects are more successful than others.
In the end, the only way to really learn what works and doesn't work is to try it out yourself. All the tips and hints in the world wont help unless you try it out yourself, but they may help you get started in the right direction.
