Is there any tutorials on how to increase a textures resolution, etc?

There really isn't a way to reliably increase resolution. Any upscaling will cause blurriness or artifacts, and won't look any better in the end. To properly make a texture bigger you'll need to recreate it from scratch.

UV maps would be about the only help the community could offer in that regard.

Well a simply way of increasing an image resolution is going to be by taking the image into Photshop or GIMP and scaling the image up by a power of 2. So for a 512x512 you would scaled to 1024x1024, 2048x2048 etc . Although now that the image is larger you must know that you cannot add data to a picture where there was no data before. This can be resolved by using enhancing filters, smudge, sharpen or blur tools etc; anything that will eliminate artifacts should work. The higher res texture may not look any better than the vanilla so really the only other option is hand crafted textures, they are time consuming and can be difficult but textures are one thing that should not be completed in a matter of moment .