The session is the period of time during which an intention is met with attention, among other resources. It is not an inconsequential consideration.

This post at Curve Writing nicely describes important components to a session of work. While OmniFocus is specifically mentioned, the crucial point was in the attempt of actively clearing the mind prior to entering a session work and then using the Inbox while in the session of work to further defer thoughts as needed.

It may not seem like a major point, but it very much is. The skill of creating the physical space in which one can develop an intention is a basic and important skill. Perhaps all skills, especially those that are basic, need regular revisiting, reviewing, and remastering.