Final answer:
The best method to assess a source's usefulness is to read it carefully for relevant evidence, critically evaluating its authority, reliability, and relevance to the research.
Step-by-step explanation:
The best approach for determining the usefulness of a source during initial research is to read the source carefully for relevant evidence. This involves summarizing the source's central idea, evaluating it for authority, perspective, reliability, validity, and potential bias, and reflecting on how the source contributes to your research. It is important to review critically and assess how the source supports or contradicts other information, the author's credibility, and how it fits into your research plan. Instead of just looking for charts and images or skimming for big ideas, a deeper examination allows you to discern the quality and relevance of the source to your research needs.