This illustration looks to have been pretty straightforward but at the same time pretty difficult. Since it is black and white, there was no use for color or any sort of gradients. However, using the line tool to create most of the shapes along with the shape tool for the tuning keys and knobs. The creator must have uses the pen tool to create some of the bends in the guitar and help make those tight curves in the body of the guitar. The shape tool was also used to create the pickups on the middle of the guitar along with the little fret markers on the neck of the guitar.
The most difficult part of this design might have been the accuracy in getting the shapes just right. It does look fairly simple with just using the line tool to create the sharp angles, but there is a lot accuracy with spacing that must be taken into account.
I like this image because it is very complex but the way the artist did it made it seem like a simple object. They may have used the pen tool overlaying the image so they could be precise. All this image needed was lines, and the ellipse and rectangle tool to form all the little shapes that make up the guitar.