Some characteristics of a good resource include authoritativeness, lack of bias, the use of logical arguments, peer review and currency. Looking for these characteristics in a resource helps ensure the material is credible and relevant to current issues.
When looking for a resource for a research paper, it's especially important to seek resources that are scholarly and include the latest findings on the topic. These resources often include academic and professional journals and clearly provide information on the author's credentials, the purpose of the research and outside references consulted.
When looking for resources in general, check to make sure the author isn't presenting a one-sided view on the topic, that all claims are backed up with unrefuted evidence and that the author has the academic or professional background to write about the topic.