Non-manifold geometry - If cleanup messes up the model. Try using the polygon select tool, checking for NMG. It will highlight the problem and you can try to manually fix it.

In many cases the only real solution is to delete the offending region and simply remodel it.

I will look through the SM tutorials and although they are not free I recall there are some very inexpensive ones that cover the basics.

Trust me investing in a few inexpensive tutorials will save you an a great deal of frustration. It is very hard to self teach yourself proper modeling work flow and UV layout and texture is orders of magnitude more complex. Trying to figure it all out on your own is a recipe for disaster.

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I can't make you a tutorial without actually shooting a camtasia loop (which might not be a bad idea to include in the sites FREE tutorial section) but I can block out the basic process:

1. "separate" the parts to be UVed by applying a number of different colored lambert shaders (See the screenshot below).

2. Select the individual colored parts by using the select faces with material. Then take a planar projection. then cut edges and unwrap and tweak UV's to create the UV map.

3. apply a UV texture Pattern to see the UV's are even. Tweak UV's as needed or re-think where you are placing the texture seams.

So here is an example of step 1...