Write like an authority: Ignore the fact that your audience might know more than you. You may not be an expert, but you are, by no means, ignorant. After plenty of research you've come to know a lot about the issue yourself. Use that knowledge to inform and convince your audience that you know what you're talking about.
Avoid deferential language such as "in my opinion" or "at least I think we should." Try not to be wishy-washy. Don't hedge your bets by arguing "perhaps we should" or "such-and-such might be the way to go." Don't be arrogant, but don't give the audience any reason to think you might not know what you're talking about.
This past year Michael Maren wrote an article for Newsweek, "The Faces of Famine." This article was not what a viewer would have expected to read: the continuation of starving people in Africa because of an apparent lack in economic means. Although most Americans are moved by the pictures of "skeletal" children and hold the belief that the problem stems from a lack in food resources due to drought and severe conditions, according to Maren the general public in the U.S. is misinformed and unaware of the politics involved with this severe famine.
The evidence Maren has compiled informs his audience that providing money donations for relief funds is destructive, not helpful, for those affected. In his essay Maren talks specifically about the situation in Sudan. The root of the famine is from a 15-year-old civil war between the Khartoum Government and the Sudanese People's Liberation Army (SPLA).
Maren has contributed both his personal experiences, living in Africa as an aid worker and journalist for 20 years, and his political knowledge about starvation being used as a weapon for a civil war, as evidence for his argument. His goals are to inform his audience what really is happening in Africa and to begin to assist in saving lives rather than adding fuel to the fire.