Prerequisite: A calendar. The one outside tool I use is an online calendar, and I put everything on this calendar, even things that aren't actually for a fixed time like "make a coffee table at the workshop" or "figure out how to recruit new PhD students" — I'll schedule them on a date when I want to think about it. That way all my future plans and schedule are together, and not a bunch of lists I have to keep track of. (View Highlight)
all sorts of productivity advice about handling it, but I find a simple flagging system is sufficient — flag Red if it's something I need to deal with, flag Orange if I need to deal with it eventually but requires some thinking or someone else to handle it, and flag Yellow for emails I send that I am waiting on a reply for, so I know to follow up later. I'll flag emails as they come in, whenever it's convenient. (View Highlight)
So my daily routine looks like
look at the daily todo list I wrote last night to find out what I'm doing today
do scheduled things on that list during the day
when I have free (unscheduled) time, do the floating tasks on my list and work on Red-flagged emails
at the end of the day4. do a quick review of Orange/Yellow emails to see if they need any handling
copy the next day's calendar items to the bottom of the text file (View Highlight)