Use this guide as a map to researching your topic in Ancient Rome, starting with the basic resources, L'Annee Philologique, Brill's New Pauly, Cambridge Companions Online, Cambridge Histories Online, Oxford Bibliographies Online: Classics, JSTOR and TOCS-IN. Another important print resource is Wiley's Encyclopedia of the Ancient World in the Perkins Library, call number: Ref D54 .E53 2013.
For a basic overview of ancient Rome, be sure to look at Brill's New Pauly.
To cite sources correctly, go to that page for examples of different citation styles. (Though you may want to investigate some of the bibliographic managers Duke has available which will import your references and automatically format the bibliography).
If you need assistance, please don't hesitate to contact me. We may be able to solve a problem via email, or we can set up a research appointment where we walk through the steps of finding sources together.
Good luck with your explorations of Ancient Rome!