How do I analyse a source?

In order to understand a source and write the best possible answer, there are seven easy steps to take: 

1. What does the source say? We need to briefly look at the source to understand what it is. For example, it's a newspaper article published in 1968, describing the Tet Offensive.

2. Where does it come from? It's a newspaper article, but who published it? Is it from an American newspaper, or a British newspaper? 

3. Why was it written, or produced? As it's a newspaper article, we can assume that it was produced to inform the public. Is it produced to tell them that the Tet Offensive was effective? Or not? Consequently, is it biased?

4. Usefulness. How helpful is it as a source in answering the question? 

5. Reliability. Can it be trusted; who posted it, and why? 

6. Context. How does your background knowledge of the Tet Offensive and the Vietnam War help?