Here's an inbox tip:
Everything worth keeping can be sorted into Today, Next, Soon, and Someday.
I like to keep Today in my inbox (but with labels applied as I've described in past posts on using Thunderbird and similar mail programs to help me prioritize and distinguish the messages I've thought about from the new, unprocessed arrivals).
I created two additional folders, Next and Soon, into which I throw any mail that I do plan to do something with, but which is not urgent.
Next is for things that I want to be sure to think about as soon as I've dealt with all of Today's stuff. In chaotic times, this can take a few days to get to, but it should not be allowed to sit stagnant for more than a week. I recommend reviewing its contents Friday afternoons and sometime midweek to pull anything to Today that can't wait any longer.
Soon is for that stuff that isn't timely or especially important, but which is of enough interest not to be immediately deleted. I get to this when I can, often when I'm stuck somewhere without an internet connection or in a logey half-hour after a big lunch. (Tip: do not stick things in Soon which the sender is expecting a reply on without first sending a short note saying "I will have to get back to you later on this." so they know you got their message).
There is a last category not entirely captured by these three; those things which are not urgent, timely or easily completed, but which seem too significant to be thrown away. These usually represent something you want for Someday. I either file these where they belong with other information (my reference folder, with the planning notes for a coming project they relate to, under the person/institution who sent the information, etc) or note the idea they represent on a separate list of Someday/Maybe projects.