A word of warning. i should have mentioned this before, but i forgot to, so please forgive me. ill be keep on adding onto this tutorial as i remember what else i miss/anything of interest/to make stuff easy for you.
Mapping textures also means moving them around in the new window which opens after you hit the edit button, so that they LOOK good as well. clear example:
as you can see there, the textures are all mapped correctly, but not placed in a way that they are aesthetically appealing to the eye. this is why it is crucial to have a second opinion, since someone else can help pick up what you miss. furthermore, as you can see, many of the textures have abrupt edges- one texture ends randomly just as soon as another one starts on another face. this is a problem as well.
number 1= distorted, unmapped/wrongly mapped faces.
number 2= correctly mapped, correctly placed (so the textures are "understandable/fitting" so to speak)
number 3= correctly mapped, not placed (just hit "quick planar mapping and left it at that"
number 4= applied the textures, did nothing to them (since you had done some mapping, it had save the co ords)
the top square (inner part) on number 3 shows what happens if you hit planar mapping, but do it along the wrong axis. this is something you have to judge on your own- which axis does the planar mapping thingy produce best looking results ( i didnt do the border around the top part, just the big middle one for 2). As you can see on 2, you notice how i placed the panels so they have an equal amount of border on all 4 sides and when i do the trimmings, it doesnt seem random anymore, but fits in? thats the stuff you need to do not just map it and leave it be.
Symmetry modifier:
This tool can be utilized both during texturing as well as modelling. a clear example is the gallic trade lane. i built 1/4th of the model, then using the symmetry modifier, i mirrored the mesh in all 3 axes, giving the final result which i posted in the thread for the trade lane. clear example: