One basis for opposing intent to use trademark applications is to show lack of a bona fide intent to use the mark at the time the application was filed.  Defending against these claims requires documentation of actual intent to use the mark as claimed in the application.  Documenting a detailed plan for product or service development and marketing is key.  For the strongest trademark position, this should be done before or soon after the application is filed.  Keeping a log of expenses and copies of communications will also help to corroborate business plans and actual steps to bring the mark into use in commerce with the applied for goods and services.  Bare allegations will not be sufficient.  The paper trail will be the documentary evidence needed to successfully defend an opposition challenge and register your mark on the US Federal Register should an opposition be filed against your application.