Cite checking is primarily about making sure the sources cited in the footnotes support the author's associated claims- and also ensuring that each citation conforms to required style standards.
From Stanford, here are some questions to consider when reviewing a footnote:
Bluebook: Many paper copies are available on reserve at the Circulation Desk. We also subsidize an online Bluebook subscription for journal members- if you do not yet have an account, reach out to your editor to get added!