Unblock quickly
"Quickly" here means both "spend <5 minutes on it" and "try to do it same-day"
If someone I manage sends me a 10-page document to review, then it might take me 20-60 minutes to review. It’s therefore a somewhat meaty task, that would be easy to delay.
But before doing the full review, I think it’s good to spend 2-5 minutes giving high-level comments, as soon as possible.
Sometimes this will immediately catch some high-level mistake or miscommunication: you can give them feedback on this mistake and they can immediately begin working on an improved version. (Whereas if you’d waited longer to give the feedback, you’d delay them.)
Sometimes you can quickly ascertain that it’s good enough, and they can progress with the project.
Sometimes you will realize that you need to review it in more depth. Maybe you have time to do the full review now. If not, spend <5 minutes giving initial feedback, focused on:
Any high-level comments that they could be working on between now and when you get a chance to properly review. This allows them to begin the fix sooner, and it will mean that the thing you review later is closer to what you want (thus saving you time on the final review).
Asking any clarifying questions that will inform your review: this could be missing information that affects your views, or it could be clarifying what sort of comments are most needed.
Often a small amount of time from you can allow your direct to move onto the next stage of their project. So make it one of your top priorities to unblock people quickly.
OK, but is this advice helpful?
Am I just saying “do this thing sooner”? Obviously it would be great to do everything sooner, but there are many priorities...
The thing I’m trying to say is: rather than waiting and eventually spending 30 minutes on the review, try to do a really quick version sooner. I think this is a more feasible thing for most people to do, even given other priorities.
Additionally: Ask your directs to tell you what sort of comments are needed (high-level comments, critiquing key claims, tweaking wording). That will allow you to spend less time on comments, and it will also mean that your direct gets the feedback that they most need (and aren’t annoyed by feedback that isn’t appropriate to the stage of the project).