There are very few policies which apply across all wikias. These can be found on Community Central.
Other policies for this wikia should be decided by the wiki community. It's generally best to keep policies as simple as possible, and not to introduce too many rules. A growing wiki can usually do well with a few simple policies and a lot of goodwill and cooperation.
Adding [[Category:Policy]] to any policy pages will add them to the policy category. This is found here.