It is often overcast around here and one cannot see the sun or any shadows.

Even when maintaining a compass course, as in steering a boat at night, it is much easier to pick a prominent star low on the horizon and guide on that, rather than deal with the frequent oscillations of the needle in your binnacle. Just check the orientation every now and then, cause them shiny things do move around a bit....

There are NO stupid questions - but there are plenty of stupid answers (though on this forum, you'll find plenty of clever answers).

There are overcasts and there are overcasts. Today was complete cloud cover in my neck of the woods, but you could still see the bright spot in the clouds where the sun was now standing. Sometimes you can't and then you are in a pickle.

Even better is night time. Learn to recognize the Big Dipper, its pointer stars and the North Star. You will have True North nailed. I used this once on an early morning start on Orizaba, the highest of the Mexican volcanoes. My companion was using his compass when I pointed out the North Star. His compass was off by about 34 degrees due to local variation (local rock with high iron content).

Prehistoric Polynesians explored and populated the entire Pacific,navigating by wave swell patterns, flights of birds,changes in the sky tint over islands,and all kinds of esoteric lore.

And Cassiopeia, on the other side of the North Star. The middle point of the W points toward Polaris, in the general direction anyway.

There is the shadow stick method;

http://www.youtube.com/watch?v=u3l49zQREcY

Works quite well if you don't mind waiting, although depending on the time of day at certain times of the year above the arctic circle could actually point you South rather than North

Doesn't work too well on the moon though as you need the light source to be non divergent i.e. a light source far enough away to create parallel rays

In the UK there is also the Satellite TV Dish Method, this can give a very accurate determination of finding True North. But this is for more urban areas.

http://www.youtube.com/watch?v=jPW8xmI4w6U

Mall Navigation fail!

Paying attention to your surroundings is key

A calibrated Altimeter can also be handy if navigating in mountainous terrain when used in conjunction with a contour map as it will give you another reference. On your contour map you will be standing somewhere on that contour line. This can help in resection problems to find your position i.e. you may only have one resection line to a compass bearing prominence to intersect with the contour line to determine your location.

There are a lot of helpful techniques and pieces of equipment, but nothing works as well as having a plan, knowing where you started, and knowing where you are located at all times. Everything else keeps you on your planned route, gets you back to it or helps you lay it out. That is why the method I use constantly and regardless of any other gear or techniques I have, is keeping the map in my hand and using terrain association. It always works, needs no batteries, and the only problems I have ever had with it was when I made a mistake and doubted what I could see with my own eyes. Build the skill and trust it. All of the other things are helpful and useful, but you still need to know where you are on the map at all times.

Yout statement nails it. It helps if you do not travel until you have resolved the problem and know where you are for sure. One of my more memorable rescues was for a young lady who lost sight of her picnic spot while out gathering wood for a campfire, became confused, and just kept walking. She was three miles away, traveling downhill into steep, dangerous territory, when we caught up with her, Had she stayed put, the search would have been over in twenty minutes, and she would not have spent a night out. A situation where packing a whistle would have been a good idea....