"there are situations where it is preferable to tone down the accent, play down the extra consonants."

Those are good ideas, Don. I'd like to ad that one of the best ways to make yourself understandable to someone with a different dialect is to slow down. You don't have to slow down much, but doing it just a little will be much appreciated.

Slowing down also helps with the elderly. Remember that they have so much wisdom and history stored in their brains already, that when someone younger speaks, they have to shove brain content here and there to make room for the new material.