One probably shouldn’t try to work on the meta level and on the base level at the same time. Go to the meta level, make decisions, write them down, plan your following tasks, schedule your next meta-level time. Then go back to the base level, and follow the plan, until you are finished or something unexpected happens. (Maybe even drink some alcohol while on the base level, to reduce your going-meta abilities. I am not completely serious about this, but a few times it really helped.)
One probably shouldn’t try to work on the meta level and on the base level at the same time. Go to the meta level, make decisions, write them down, plan your following tasks, schedule your next meta-level time. Then go back to the base level, and follow the plan, until you are finished or something unexpected happens. (Maybe even drink some alcohol while on the base level, to reduce your going-meta abilities. I am not completely serious about this, but a few times it really helped.)
That’s about my theory as well, even down to the booze to turn off the inner Critic.
However, in any problem solving enterprise, “something unexpected happens”, and the wheels start spinning.