Lately i've been spending a lot of time studying materials and mapping methods. UV Mapping is a complex and frustrating art, and trying to get a clean layout is difficult for anyone starting out. A friend shared a few things with me to help me along, and what i've learned so far is that its best to aim for a layout with all uv chunks split at the hard edges. Not only does this help to achieve a smoother mesh, but it allows you to texture corners with no obvious seams. For example, i could texture rust around a corner without a split on the edge, which would look really bad to the observant.
Another frustration i've had lately is to actually understand the differences between object-space and tangent-space normal mapping. Especially generating a good one. I frequently use
Crazybump to generate Normals from height maps, but I really need to be using Zbrush to generate them. Not only will they come out better, but they will be more exact since they are created from a high poly model.
I found an excellent article on this subject
here. Maybe if you are interested in the subject, it will be of use to you.