Well this may not help but I'd say keep at it.

I have been having a few problems myself (this is my first game model texturing experience and first humanoid complete uv unwrap so you aren't alone int he wow this is a big task thing).

I found the best thing is to look at your model and pick one part and then work on that part. Looking at a whole scene and thinking 'OMG I haven't textured it yet' is depressing.

I find now everything is mapped (and what a process that is) taking one thing into PS to work on is actually quite a relief.

Pick something small from your scene and try applying the tutorials to it - there are some good PS metal ones on the net that are easy to follow for example and I am sure you need something metal! Once you have one thing it'll get easier.

And now I must return to ripping out my remaining hair over dwarf beards 8).

Don't quit now!