If you are headed towards the Dayspire, then you are facing the direction known as Dwarfward, for obvious reasons. Much like the North Star in our world, Dwarfward is a naturally occurring compass point. It can even be seen at night, as there is a faint nimbus of Positive Energy illuminating at least one of its edges, much like an aurora. (Interestingly enough, a truly skilled outdoorsman can look at the degree of radiance on either side of the Spire at night and estimate the number of hours until dawn.)
Facing Dwarfward, the direction to your right is known as Deosil, which means "sunwise" in Elven. This is the direction to face to watch the "sunrise" as the Dual Suns emerge from the vertical horizon of the Dayspire. Similarly, on your left is where the suns "set", and while the proper Elven term for this is Tuathal, "fatal," most folk know it as Widdershins, a term coined by a rakish Halfling wind-sailor long ago. Directly behind you is Wayward, which is a corruption of Away-ward, in the sense of "away-from-us-ness", but since this direction leads away from civilized lands and into danger, the definition of "willful deviation from the expected norm" is most apt.
You would think that this system would make navigation throughout Pellatarrum quite easy, but you would be wrong in that assumption. The kink here is that, when it comes to overland travel, only two of these directions -- Dwarfward and Wayward -- are objective. Both Deosil and Widdershins are subjective points in a rotating system; specifically, they are not straight lines but are curves. Which means you can throw your Cartesian coordinate system out the window, because you can't navigate if your Y-axis is curved.
Well, okay, you could if you had a sextant and knew enough trigonometry to triangulate your position, and then triangulate your destination, and then do some math which I can't even comprehend to find some kind of vector between the two. I doubt that many people in Pellatarrum would have the knowledge of advanced mathematics to pull this off, and those who do are probably wizards, in which case it's just easier to use magic.
So here's what it boils down to: If you are just traipsing around in your local county woods, fine and dandy. But the moment you want to engage in significant overland travel without a clearly-marked road, you need one of three things:
- a map between point A and point B, which you can use to navigate through terrain association (which is a fancy way of saying "That mountain there looks like this mountain here on the map, so we go this way"). Of course, this technique is very black box -- either you know where you are on the map or you don't, at which case it ceases to be useful;
- significant experience between points A and B, so you can go "Oh, I remember this boulder, and just a mile past it is a game trail which takes me to a river which leads to etc..";
- a Ranger or Druid who, due to their mystic connection with the land, can overcome this "navigational Coriolis effect" and actually lead you to where you want to go through dead reckoning and sheer ballsiness.
This last point merits some attention. Certainly, anyone can learn the Survival skill, and use it to follow tracks, hunt game, and survive in the outdoors. This much is unchanged from the rulebook. But the moment the Game Master needs to break out the rules for getting lost (page 424 in the Pathfinder Rulebook), if you are more than 10 miles from civilization and you do not have one of these two classes, you cannot roll to get un-stuck. You are lost and will probably die out there (which is why it's called wayward, after all).
And no, you cannot navigate at night using stars, because there are no stars to use. Between the Elemental Churn and the Seasonal Clock, the sky is an ever-changing mess to the untrained eye. Only Druids and Rangers, in a kind of navigational augury, can spot the few fixed points within the Elemental Planes above and use them to determine location and bearing upon the surface of Pellatarrum.
Don't fall off the map.