I used to write for a newspaper and went to journalism school. The first thing you learn is the "inverted pyramid" style. Basically meaning, put the most important stuff at the top. Work your way down from there, with less important details being lower in the story.
Of course, it depend on what kind of article -- hard news, feature news, etc. -- you are writing. If you have direct quotes from anyone, lace a couple of those in there. With news writing, it's always important to say where the information came from by including things such as "he said" or "according to ..."
Remember that being concise is good. Keep paragraphs short -- one to two sentences. This is typical for newspapers anyway. Magazines can tend to have a bit longer paragraphs.
If you're still stuck, try going online and reading a few different kinds of stories, see what works for you.
As far as base guidelines for interviewing people, I try to come prepared with at least a few questions in case I get stuck. Always think of the basics: who, what, when, where, why, how. Then think about what you would want to know if you were reading the story and try to let the conversation flow when you can.
