Have you ever wondered why the answer to the problem that you have been trying to solve pops into your mind just as you are driving home, taking a shower or waiting in the queue at your local takeaway? The answer is that your Creative Right Brain has been thoughtfully working on the problem for you. So how does this happen when you have been wrestling with a particular conundrum all day?
Although not completely physiologically correct there is a useful Left Brain/Right Brain model that we can use. The left side of our brains is logical, linear and provides filtering of ideas, so although it will provide solutions it also has a nasty habit of saying 'but it won't work', 'that is not a good idea' or 'the boss will not be happy'.
The right hand side of our brains is linked to creative behaviour and does not have these filters thus increasing the range of possibilities. The problem is, how on earth do we hand our problem to one and not the other? Simple, we play tricks on it!
If you have something really tricky to work on then you should get stuck in at the start of the day (this trick works in a workshop environment too). Really get to grips with every facet of the problem, all of the bad bits, barriers or desirable outcomes. You are trying to mimic the situation where you work all day, drive home and experience the Eureka moment, except that we are trying to save you working all day and then going home late.
Back to the problem. Your logical Left Brain should really be getting stuck in so now is the time to hand over the problem. Go and get on with something else, distract the Left Brain and let the Right Brain do the work. This is what driving home or having a shower does when you have been working late. Distraction is important here, simply pretending to be busy or waiting will not work. The answer (or answers) to your problem will probably come to you at an unexpected or possibly inconvenient moment so remember to have a pen and paper handy at all times.