Here are some things to look for in scholarly book resources:

• author or editor: are the authors or editors scholars in the field?  Do they hold a PhD in a relevant field?  Are they a professor at a college or university? Are they practitioners who work in an related area?  If you can't find anything about the author or editor in the book, google them and see if they have a website or page on their institution's website.
• publisher: who is the publisher of the work?  Scholarly publishers include university presses (Harvard, Oxford, UNC, NYU, etc...), scholarly organizations (IEEE, SBL/AAR, Institute for Global Environmental Strategies), and commercial academic publishers (Brill, SPRINGER, Routledge, Taylor & Francis, etc...).  If you have a question about the publisher, google their website and look at their "about us" section.
• date of publication: generally the more recent the date of publication the better, especially in the sciences and social sciences.  When dealing with issues of race, gender, ethnicity, sexuality, or class, publications after 2010 are preferred.  
• citations or bibliography: what types of sources are cited in the book?  Are their a sufficient number of sources for the length of the book?  Can you locate new resources from the bibliography that will help in your own research?
• tables of contents, acknowledgments, or introductions:  these sections at the beginning of a book can help you decide if it will help answer your research question, and which part of the book to start with.

Here are some things to look for in scholarly journal articles:

• page length: in the arts and humanities, scholarly journal articles should be at least 8-10 pages, and will likely be in the 15-25 page range.  In the sciences and social sciences, scholarly journal articles may be less than 8-10 pages in length, but should conform to the standard format of a scientific article (see below).
• author: are they a scholar in the field?  Do they have a PhD in a relevant field?  Are they a professor at a college or university?  Articles published in the science and social sciences frequently have multiple authors, sometimes 10+ authors for one article.  Check with the rules of the citation style you are using to see how to format citations for resources with multiple authors.
• journal:  google the name of the journal your article is published in if it is unfamiliar to you.  Look at their website and the "about us" section.  Journals can be published by university departments, scholarly associations, university presses, and commercial publishers.  
• date of publication: generally the more recent the date of publication the better, especially in the sciences and social sciences.  When dealing with issues of race, gender, sexuality, ethnicity, or class, publications after 2010 are preferred.  
• citations or bibliography: what type of sources are cited in the article?  Are there a sufficient number of sources for the length of the article?  In most articles, the first several pages include a literature review section which can be very helpful in building your own reading list.
• abstracts, introductions, and conclusions: reviewing the abstracts (summaries), introductions, and conclusions of articles can let you know if an article is likely to answer your research question.
• article sections: most articles in the humanities, and all in the sciences and social sciences, will include section headings in the body of the article to help with organization and comprehension.  In the sciences and social sciences, there is a standard outline that is followed: abstract, introduction, materials and methods, results and discussion, conclusion, references (bibliography).  See an example here.

Here are some things to look for in websites:

• author or editor: can you find an author or editor for the information that is posted on the website?  Are they scholars in the field, or have a PhD in a relevant field?  If you can't find the name of an individual, there may be an organization, board, or committee responsible for the website content.  Check the "about us" section of the website to find out more information.
• publisher: in the case of websites, this is usually the sponsoring organization or entity behind the website, such as a university, government organization, cultural organization, or company (.edu, .gov, .org).  Again, the "about us" section can be a good place to start to find out more, but googling or looking at their entry on Wikipedia may give you a better idea of what they really do.
• date of publication: look for information to indicate the last date that the page was updated.  This may be the copyright date at the bottom of the website, other information on the site that refers to specific events, or bylines, in the case of news organizations.  If the last date you can find on the page is more than 5-10 years ago, is the information you are referencing time-sensitive?  For some topics, that might be fine, for others it might be out of date.
• citations or bibliographies: does the website indicate where the information posted comes from?  Do they cite the sources they used to prepare their own information?  Citations may be indicated by links within the content of the page, or referred to within the text, rather than compiled at the end, as they might be in a book or journal article.
• charts, data, images, etc...:  does the source take advantage of its online format by including visual content?  Is it presented in a straight-forward way that doesn't appear to be manipulated.