A good source for information on occupations is the Occupational Outlook Handbook, found in the library database: Career & Technical Education (found under Databases by Title). Type in the job--graphic designer for example--and Occupational Outlook Handbook. Select the entry with the most recent date, then click on the Save as PDF tab to open in Adobe. Information on required education, job outlook, median salary, work environment, and similar occupations is given. The "Cite" link will give you an APA or MLA citation.
The Handbook is also posted online by the U.S. Bureau of Labor Statistics: http://www.bls.gov/ooh/
Another helpful online source that gives updated occupational information and labor market research is O*NET OnLine: http://www.onetonline.org/
If more library database articles are also required, try Credo Reference, which has all reference book content, Films on Demand for streaming video, and a number of others for magazine/journal content.