Concentrate your effort on completing the most important tasks as
chosen by your customer, instead of having several unfinished tasks
chosen by the developers.

It
may seem silly if your iterations are only one week long to make a new
plan, but it pays off in the end. By planning out each iteration as if
it was your last you will be setting yourself up for an on-time
delivery of your product. Keep your projects heart beating loud and
clear.