This seems so small that it’s silly to even discuss, but I use it all the time.
I’m the sort of person who is easily distracted – it’s seemingly part of my nature, plus life throws lots of interruptions my way! So I benefit from a super ridiculously obvious way of answering “what am I working on at this moment?” So when I’m distracted, I can remember to go back to it.
My solution: in any agenda note, type \remind(1m) to create a reminder one minute from now.
One killer feature of Apple Reminders is that they persist. When they show up on my phone, they stay on the screen until I explicitly clear them. All other apps have their reminders clear away after viewing them one time.
When I’m on my Mac, I don’t need the reminder in the corner of the screen – so I clear it out, and look at the side bar in Agenda for the now-overdue reminder.
Bonus tip: I usually have a “today” note. The other thing I do is add a 
prefix to the item I’m currently working on, so I can find it just by glancing at the note. Then I don’t need the reminder.
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Another bonus tip 
I use a #focus tag to create a “mini agenda” of related notes for the item I’m working on, that way I don’t have to look at any unrelated notes (they still distract me even if they’re collapsed OTA). My top smart overview is for this tag.