Yeah. Anything simple. 2 tone paint scheme or something... once you get everythng lined up (wireframes are your friend) then start adding more detail. If you start trying to do something difficult, you'll only get frustrated with it. Who cares what it looks like in the end, as long a you're learning how to skin... Good designs will come later once you get the basics down. But if you're itching to do something cool but easy then try skins like the marlboro paint scheme, or old pennzoil, etc... those cars looked good AND are fairly easy skins to start out on.
now as for layers... Everyone does things differently. I use mostly vector based software, so every decal is its own object and such (making editing pretty easy) but there are alot of nice things about working in raster also. Some people will put EVERY decal on its own layer, some people will leave layers out, etc... it all depends on what you become comfortable with.
Here is a basic skin i developed, and I will break it down into design and layers:
The design was developed in a Work In Progress
THREAD HERE.
In it, I explain how I usually develop skins on paper before it ever hits the computer.
Lets break the skin down into layers from Top (1st listed) to Bottom (Last Listed). Notice the transparency in each:
MASK LAYER. This layer actually helps to bring your file size down by covering all 'outside' areas with a flood of one color. Its also not a bad idea to put credits on this layer (or above it)
WIREFRAME LAYER. Obtained from the skinnerz kits, this layer is extremely useful and aides in lining up graphics from one side of the vehicle to another. On a finished skin this layer will be turned off, but often times when developing various elements of a skin, you will turn this layer on so you can see how the wireframe is laying on the body of the vehicle, and how your graphics are lining up in relation to it.
BODY LAYER. Some people dont add this layer, but i usually include it with some form of DARKEN or MULTIPLY transparency on it. It adds a bit of depth/shading to the skin. The transparency will make it so it shades all layers underneath this layer. You would normally not see any white through this layer because of the darken or multiply, but there's an issue with converting my vector to photoshop to .png, so the image shows white here. This issue is why i put my shadows and highlights on separate layers (see below). But the important thing is, you dont want the white in the raw body image to wash out any of the underlying layers. It should only cast shadows/darken the underlying layers somewhat.
SHADOWS LAYER. Completely optional. Some skinnerz like to make body kits or custom bits, and generally those bits go here, or on the body layer above. In this case, the shadow layer contains all of my dark shadows. Sometimes its shadows from suspension, or body lines, etc... Almost always it involves transparency Darken or Multiply.
HIGHLIGHT LAYER. Like the shadow layer above, this one contains highlights, and also uses transparancy. But this layer will use Tones of white, and involved Normal or Brighten transparency.
DECALS LAYER. The decals layer is self explanatory, as it contains all of the various decals that go onto the vehicle.
CARBON FIBER LAYER. This layer is custom to this skin. I had to put it beneath the decals layer (so decals could go over the top of carbon fiber bits) but it had to go over the paint layer (to cover the painted bits). Not every skin is going to have carbon fiber. But this is a good example of a custom layer/bit that needed to be added and fit in. Other layers such as dirt, or dust, etc can be added into the mix in a similar fashion
PAINT LAYER. The final (bottom most) layer of any of my skins. it contains the base coat paint and striping. Don't be overly concerned about how the paint lies outside of the wireframe, because it will get covered by the MASK layer.
There is another layer that is not shown, because it is completely transparent. But it is an Overall Size layer. This layer is a rectangle which fits the dimensions of the wireframe or mask layer, and is used as reference when making decals or paint etc. You want to stay within the confines of this rectangle, because if any graphics extend beyond the rectangle it will affect the exported file. Im not sure how photoshop handles anything that runs off the page, but in my vector software you need to clip any shapes running off the edge or it will affect the proportions of the final art. This also helps when you want to export out a single layer to share with someone else. I can export my shadows (with my overall size layer) and then another skinner can size it to fit and center it easily on his or her skin without having to reposition it.
A basic layout of the skins and how they go together. Its rough but you get the jist. Also, the wireframe layer can go just about anywhere. You will move it often during the development process.
It is worth noting that all of the images above have been scaled down drastically to fit in the website easily and keep file size down somewhat.
Typically you will want your final skins to be 2048x2048 at a minimum. So your working skin files should be at least that (if not more). This is also why I prefer vector over raster, it helps to keep the file size down due to all of the layers.
If you haven't realized already, the skin files used are square in proportion, but the images you see above are rectangular. There is information on this site regarding changing the proportions of the working files, and exporting them back out as square .jpgs for finals.
For additional info on layers/shading check the
1st post in my skinlab.