Use a paper “response list” to triage messages before you do any follow-up.

The solution to e-mail overload is pencil and paper? Who knew? Grab a legal pad and label it “Response list.” Run through your incoming e-mails. For each, note on the paper what you have to do or whom you have to call. Resist the temptation to respond immediately. If there’s important reference information in the e-mail, drag it to your Reference folder. Otherwise, delete it. Zip down your entire list of e-mails to generate your response list. Then, zip down your response list and actually do the follow-up.
Source: Tips for Mastering E-mail Overload

Hmmmmmm…. My triage technique has been to color code and automatically flag certain messages. I know which are related to which of my job hats, whether or not they are priority people, and which are past the 24 hour response deadline.