It may not be possible in all cases, but if you are preparing a manuscript for publication and there will be delays for review, you can give a tentative descriptive citation, rather than a formal one, marking the other work as "forthcoming". This will probably be fine for the purposes of review and you can correct the citation before final publication.
It might also be possible, in some cases, to contact the author(s) of the other work for their "best guess" as to these things and mark the citation using their words but as a "private communication, publication forthcoming". It is fairly common to mark some citations in new work as private communication, actually.
But it is possible that the work you want to cite won't, in fact, ever be published, so you need to be a bit tentative, both in the short term and possibly for final publication of your work.