Greetings!
I think it's great that you are willing and wanting to learn! I can remember when I first had to write a research paper (back when dirt was young!), it seemed like an insurmountable--and horribly confusing--chore. But, as with everything else in life, it's just a matter of starting at the beginning and building your skills and confidence. You are right that narrowing a topic can be a challenge. What I try to do, if I have to take something as broad as the Vietnam war, is to start by making a list of possible sub-topics. For example, you could write about the political history that led to the Vietnam war; why America chose to get involved and what the effect was on American society; the devastating medical effects of chemical defoliants; France's involvement and eventual defeat in Indochina, leading to America's involvement in the region. Try reading through some books and encyclopedias on the subject, and consider whether any of the sub-headings would make a good "narrowed" topic.
Writing about a person without making it biographical usually requires looking at the accomplishments of the person and making their works your focus. For example, you could find plenty to say about William Shakespeare, of a non-biographical nature, by focusing on his plays and other works. You could discuss the role of religion in his plays, or the supernatural, or mythology, or many other avenues of approach. If you were going to write about, say, Rosa Parks, you could focus on the segregation laws which led to her defiance on the bus, which sparked the Montgomery, Alabama bus boycott that eventually led to civil rights for African-Americans.
I hope this helps explain it a little better!
Thanks,
Sarah, EsayForum.com
Sarah, EssayForum.com