[happyrock]

As recommended in Deep Work (one of the best productivity books around), I try to schedule my whole day in my calendar at the start of the day, with specific deliverables/outcomes for each block of time. Even if I don't finish everything or I end up deviating from the plan (it happens often), just doing this at the start of the day imposes a certain structure that your brain tends to internalize, which in turn provides mental clarity. Try it.