Stas, try to learn to work in two modes: a creative, thoughtful one for complex, productive tasks, and a fast one for routine stuff and admin work.
Writing a marketing strategy, working through ads for contextual advertising, analyzing sales: tasks like these need immersion, slowly getting into the material and tuning in. They’re worth scheduling for the most productive part of the day. For me that’s the morning. For night owls, probably the other way round. I called this mode deep dive, or just “dive”. It’s also fashionable to call it a state of “flow”, but that’s down to luck.
The second mode is “stealth”. In it you scatter a crowd of Agent Smiths with quick, precise blows: you go through email, answer on Slack, check interns’ test assignments, change passwords and give access to whoever needs it.
It’s important to recognize in time that the task in front of you is unimportant, and to handle it in stealth mode.
Mark such tasks in advance with a “stealth” context tag, if you follow GTD and use contexts. Or make a checklist of quick jobs and work through it at a set time.