On Wikipedia, I'm mostly a content creator/reviewer, although I jump in at NewPages and RecentChanges sporadically (mostly when I'm bored). I'm also an administrator, although that's not the focus of my contributions – I'm more of a content admin.
Reviewing FAC: I rarely support on the basis of a source or image review, although I may oppose on the basis of either. If I oppose your FAC, I'm open to revisiting if and only if the issues I point out have been addressed, either through edits to the article or with a cogent argument for or explanation of the status quo. If I give a specific example of an issue (particularly if I say "For example"), this is likely not the only occurrence of said issue in the article, and you should check for other instances before asking me to revisit. If any point in my review is unclear, feel free to ask. I watchlist all reviews that I comment on, so you needn't ping my talk unless I've not responded for a few days.
FAR: I'm a delegate at FAR, so I review there rarely and beg for updates and more opinions regularly. We need more reviewers. If you're reading this, go review now. Srsly.
DYK: I occasionally review articles in preps/queues at DYK. Any found to contain serious sourcing issues (including but not limited to copyvio, extensive or blatant close paraphrasing, and extensive use of unreliable sources) will be removed unilaterally and immediately, without prior discussion. If less serious sourcing issues occur, or if the article is still at T:TDYK, I will point out problems on article talk or the review page.
Other: many of the FAC points apply. As FAC is where I am currently reviewing most often, my reviews in 'lower' areas (particularly MilHist A-class, which I'm beginning to get into) may be too strict. If that is the case, feel free to point this out.