On the discussion pages, the group of people editing a particular Wikipedia article will discuss additions or deletions to the article.  They will point out where citations are needed, where there may be biased statements, grammar mistakes, and other violations of Wikipedia policy and practice.

Make sure to check the badges at the top of the Discussion page.  If the article has some, they can be great tools for evaluating its quality.  Here's an example of one:

And another: