Well, good to see that despite the fact that you're extremely presumptuous, you do know a few things.
Glad you noticed. Unlike some on the interwebs, I don't talk about things I don't know about. Unless I have personal experience on a topic, I'm reluctant to even offer an opinion. Unfortunately, most opinions are based 3rd party info, wishful thinking or based on knowledge gleaned from a movie.
I'm actually referring to determining direction based on the position of the sun in the sky and the current time. I learned it as a kid and have used it many times:
*Edit (more concise reference):
http://www.wikihow.com/Use-an-Analog-Watch-as-a-Compass
I'm familiar with the technique. Tried it once or twice when in the scouts. I'd rather carry a compass and a map and leave the parlor tricks for when you have no proper equipment. Primitive survival is what you do when plans fail, not what you do for an enjoyable weekend. just my $.02
I don't think a sextant would work in most cases as it relies on the horizon - this is primarily for navigation on the sea. Although it would be more than adequate if it did work --- but then you'd have to be carrying a sextant. If you forget your compass but have a sextant, you have other problems.
lol
Moss growing on trees is a trick I've verified on many occasions. It's not an old wives tale. As the sun traverses the sky, it spends a great deal less time (in our hemisphere) hitting trees on their north side. This means they are generally cooler and wetter on this side - more moss grows. Obviously there are conditions which can affect this, but if you know what I've written in this paragraph and are a little observant, it can be quite helpful.
I've looked and looked and pretty much found moss growing at the entire base of most trees I've checked. Even going by where the thickest moss was located was very inconsistent with this theory, hence my opinion that the theory was invalid. Be aware most of my experience is in Arizona. Further North, the theory may be sound.