Assembling Supplementary Materials
There are no hard and fast rules on exactly what supplementary materials you should assemble. You must include the formally required elements, but any supplementary information can be included or excluded at your discretion. Keep in mind that you have one chance to introduce your organization to an IRS agent who has never heard of you or your group. In the course of that introduction, you must clearly document the fact that your organization understands the legal language governing a nonprofit organization.
The agent will be familiar with Form 1023. It details your financial history and is, to some degree, presented on good faith by all parties involved. The supplemental materials should drive home the fact that you are a viable organization with media coverage, regular recorded meetings, classes open to the public, an engaged and supportive membership base, and a community already aware of and committed to supporting you in a number of ways.
The reason you want to have a clear media strategy and cultivate good contacts in the local press is to increase your media coverage because you can use samples of that coverage to document your activities to the IRS. These early budgets and program samples can help show that you are a viable group, actively doing what you say you are doing.
There is also no definitive rule on how much assembled sufficient material to include with your application. What is important is that any activity you reference in your narrative or any line item in your budget that has a real, tangible result will help your case.