Use this time management story to show how planning is the key to time management.
Start with a bucket, some big rocks enough to fill it, some small stones, some sand and water.
Put the big rocks in the bucket - is it full?
Put the small stones in around the big rocks - is it full?
Put the sand in and give it a shake - is it full?
Put the water in. Now it's full.
The point is: unless you put the big rocks in first, you won't get them in at all.
In other words: Plan time-slots for your big issues before anything else, or the inevitable sand and water issues will fill up your days and you won't fit the big issues in (a big issue doesn't necessarily have to be a work task - it could be your child's sports-day, or a holiday).