If you use a Google mailbox and are interested in keeping up with everything, try setting up a few new features and making it your assistant. In Google Labs, enable the "additional folders" and "super tags" options.

Then, in the main options, configure the super tags as follows:

The ones shown here denote the following (from left to right):
Red ball is an urgent matter, search for has:red-bang (or l:^ss_cr);
Yellow ball – the case can wait, search for has:yellow-bang (or l:^ss_cy);
Red asterisk – included in the Calendar, search for has:red-star (or l:^ss_sr);
Orange arrows – instructed, search for has:orange-guillemet;
Purple question mark – requires completion or study, search for has:purple-question (or l:^ss_cp);
Purple asterisk is a long–term business, search for has:purple-star (or l:^ss_sp);
Green check mark – completed, search for has:green-check (or l:^ss_cg);
Green asterisk – archive, search for has:green-star (or l:^ss_sg);
Blue information icon – archived from the general link has:blue-info (or l:^ss_cb).

Letters with a "red ball" should not hang in the mailbox for a long time. If you are going to do something, then do it, if not, get rid of the junk in the mailbox.

Use shortcuts to sort emails by Content, Projects and Sources, adding the prefix M/, P/ or And/ respectively.

Examples of content:

With/Meetings
With/Computer
With/Business Trips
With/House
With/Personal

Examples of projects:

P/Company website
P/Spring break
P/Skateboarding Championship

Examples of sources:

And/Jones, Steve, lawyer
And/Joe Thomas

Switch the super tags to arrange the letters in the right order. By labeling them, you will know exactly what you are working with and how to manage your projects.

Save regular search queries using Gmail bookmarklet generator (Gmail bookmark generator). Using the same queries, you get buttons that can be dragged to the toolbar. Let's say you want to see the tasks assigned to assistants (under the orange arrow) – go to the site and enter l:^ss_co.

The Title will be displayed on the button, so I'm coming up with a name that will make it easy to find everything later. Then click on the "Generate" button. And just drag the button to the toolbar.

Turn Gmail Into Your Ultimate GTD Inbox [Adam Pash]