Dorothea Brande was an American writer and author. In her book, Wake Up and Live, she describes 12 mental exercises to help make your mind sharp and more flexible. (She wrote these in 1936 so they may have to be adapted but they are still applicable.)
Try your hand at one of two of these each day and open yourself up to new situations and solutions:
Spend an hour each day without saying anything, except to answer direct questions, in the midst of the usual group, without creating the impression that you're sulking or ill. Be as ordinary as possible. But do not volunteer remarks or try to draw out information.
Think for 30 minutes a day about one subject exclusively. Start with five minutes.
Write a letter without using the words I, me, mine or my.
Talk for 15 minutes a day without using I, me, my or mine.
Write a letter in a “successful” or placid tone. No misstatements, no lying. Look for aspects or activities that can be honestly reported that way.
Pause on the threshold of any crowded room and size it up.
Keep a new acquaintance talking about himself or herself without allowing him to become conscious of it. Turn back any courteous reciprocal questions in a way your auditor doesn't feel rebuffed.
Talk exclusively about yourself and your interests without complaining, boasting, or boring your companions.
Cut “I mean” or “As a matter of fact” or any other verbal mannerism out of your conversation.
Plan two hours of a day and stick to the plan.
Set yourself 12 tasks at random: e.g., go 20 miles from home using ordinary conveyance; go 12 hours without food; go eat a meal in the unlikeliest place you can find; say nothing all day except in answer to questions; stay up all night and work.
From time to time, give yourself a day when you answer “yes” to any reasonable request.
(Information from Gretchen Rubin, www.yahoo.com/shine)