What I have done with my sketches is, I have scanned my sketches in and darken the images using the blending tool on Photoshop and adjusted the brightness and contrast, to really make the sketches pop out the page, and having a crisp image.

Rock Formation

After refining the images on Photoshop, I have made a page where I have played with the composition and layered the sketches on one page, to show all the sketches on one page. I will be following this method a lot when I am specialising in my practice, concept art design.