Search government databases on a specific topic to gather facts and figures for the main points of the argument. Use things like census data, economic reports, unemployment numbers and tax revenue to bolster an opinion. Begin this process at a college or university library or an online search engine. A paper on homelessness containing government figures about how many people are homeless, unemployment figures within the homeless community and how much nonprofits spend on operating shelters for those without a place to live all make an argument stronger. In a persuasive paper about education budgets, writers can point to the amount of tax revenue a particular community receives every year. Persuasive papers about how America is losing the war on drugs can cite government data to show how much money the government spends on fighting illegal drugs in the United States.
Talk to people regarding the topic who might advocate for a particular point of view. Interview them about how they get their point across and what communication tools they use to persuade an audience. In writing a persuasive paper that attempts to help people lose weight, take the time to interview people from the American Lung Association or a medical doctor to find out what research and ideas work most effectively. Writers putting together a paper on persuading people to give more to a nonprofit should talk to nonprofit organizations with successful capital campaigns to get their secrets. A persuasive paper addressing the importance of moving from welfare to work should include personal stories from people who made the transition and perhaps those who helped. Talking to people helps to sift through ideas and subject matter that may or may not work for the interest of the writer.
Read the editorial page of local and national newspapers to get the pulse of hot topics. Look through opinion magazines where authors write about all kinds of subject matter. Scan the blogosphere as an additional resource of information. Editorial pages typically jump on something said by a politician or someone in a leadership role and argue a different point of view. Journalists act as the so-called "fourth branch of government" and a watchdog in the community. They spend their careers watching out for others so do not discount their expertise. Reading through this material at libraries, bookstores and coffee shops make it an inexpensive way to research a persuasive paper topic.