Maintain focus

Being able to do two things at once might seem like the epitome of efficiency - why waste time doing just one task when you can complete two simultaneously?

However, famously there is a belief (myth?) that women can mulitask but men cannot - hampered by having a 'one track mind'.

In the real world, rather than the world of gender politics, multitasking seems to be unfruitful, since in practice the work style is not multitasking but micro-sequencing of two parallel tasks.  The problem is that the brain switches so often between the two tasks and focus is lost on each switch and there is a delay each time the switch occurs.

So, stick to one task, focus and concentrate, complete it - and then move on to the next task. You will be more productive.

This 'principle' - of focus until complete - works with all activities. Executing a strategy, a production plan or a major project requires each stage to be complete.  Don't switch attention to the next stage whilst finishing off the first.