I've often had an "aaah #$%^" moment in the shower, during a "bio break" or while driving. If I get stuck for more than an hour then I go home and will often figure the problem out.
One strategy that seems silly, but often really works, is to have a whiteboard in a room with a teddy-bear in a chair. If you get stuck then go explain to teddy how it works. In doing so you'll often find the problem.
Good..normally the biggest problems are solved when you change the envionment, i guess if we keep working in the same place and keep seeing the problem we tend to ignore minor problems that are actually the cause.
Replay available now: A handful of emerging network technologies are competing to be the preferred wide-area connection for the Internet of Things. All claim lower costs and power use than cellular but none have wide deployment yet. Listen in as proponents of leading contenders make their case to be the metro or national IoT network of the future. Rick Merritt, EE Times Silicon Valley Bureau Chief, moderators this discussion. Join in and ask his guests questions.