If you are like me, you will find that the FAQ is sorely lacking in its description of how to get Mezzanine working as an app. So here is what I did (after a painful half day of hacking) to get it integrated (somewhat):

1. Download the repo and copy it into your project
2. Run setup.py for the package
3. cd to the package and run the mezzanine command to create a new app (mezzanine-project <project name>), let’s say you use the name blog as your <project_name>.
4. In either the local_settings.py or settings.py file, set the DATABASES dict to use your project’s database.
5. Run the createdb command from the mezzanine manage.py file

Now it’s time to start the hack-fest:

1. In your project’s settings.py file, add blog to INSTALLED_APPS
2. Add some configuration variables to settings.py that Mezzanine is expecting:
   
PACKAGE_NAME_FILEBROWSER = "filebrowser_safe"
PACKAGE_NAME_GRAPPELLI = "grappelli_safe"
GRAPPELLI_INSTALLED = False
ADMIN_REMOVAL = []
RATINGS_RANGE = range(1, 5)
TESTING = False
BLOG_SLUG = ''
COMMENTS_UNAPPROVED_VISIBLE = True
COMMENTS_REMOVED_VISIBLE = False
COMMENTS_DEFAULT_APPROVED = True
COMMENTS_NOTIFICATION_EMAILS = ",".join(ALL_EMAILS)
COMMENT_FILTER = None

3. Add some middleware that Mezzanine is expecting:
   ““
   …
   “mezzanine.core.request.CurrentRequestMiddleware”,
   “mezzanine.core.middleware.RedirectFallbackMiddleware”,
   “mezzanine.core.middleware.TemplateForDeviceMiddleware”,
   “mezzanine.core.middleware.TemplateForHostMiddleware”,
   “mezzanine.core.middleware.AdminLoginInterfaceSelectorMiddleware”,
   “mezzanine.core.middleware.SitePermissionMiddleware”,

   Uncomment the following if using any of the SSL settings:

   “mezzanine.core.middleware.SSLRedirectMiddleware”,

   “mezzanine.pages.middleware.PageMiddleware”,
   ….
   ““

4. Add some INSTALLED_APPS that Mezzanine is expecting:
   
....
"mezzanine.boot",
"mezzanine.conf",
"mezzanine.core",
"mezzanine.generic",
"mezzanine.blog",
"mezzanine.forms",
"mezzanine.pages",
"mezzanine.galleries",
"mezzanine.twitter",
....

5. Add references to the template folders of mezzanine to your TEMPLATE_DIRS tuple
   
os.path.join(BASE_PARENT, '<path to mezzanine>/mezzanine/mezzanine'),
os.path.join(BASE_PARENT, '<path to mezzanine>/mezzanine/mezzanine/blog/templates'),

6. Finally, if your like me, you’ll have to override some of the extends paths in the mezzanine templates, the most obvious being in “blog_post_list.html” which just extends base.html, instead you want it to extend the mezzanine specific base file. So go to that file and replace the {% extends "base.html" %} with {% extends "core/templates/base.html" %}.

This is covered in the FAQs:

http://mezzanine.jupo.org/docs/frequently-asked-questions.html#how-can-i-add-mezzanine-to-an-existing-django-project

TLDR: Mezzanine adds a handful of settings, apps, middleware and context processors, all defined in its default settings.py file – you just need to extract enough of those, depending on your needs.