• Quality, in this case, really refers to the suitability of your source for your academic research. Generally, you want academic sources, but even newspaper articles might be appropriate depending on your need.
• Think critically - We all evaluate the trustworthyness of advertizing, billboards, news shows, and other information every day. The same critical-thinking that goes into deciding what ads to trust goes into deciding what articles to use.
• Think in terms of of your source's sources, intended audience, language and where it is published.

There are many strategies for determining the quality and scholarliness of your sources. Here are a couple options.

Use these resources for information about and help writing academic articles, papers, research reports, etc.