How to transfer a inmage onto the wall?

Well you could I suppose draw a very simple version of the guitar... then use math and scale it up... use a starting point in the center of the pix to begin your scale line... you can do this onto tracing paper that you can buy in large sheets at the fabric store... (they call it something else, it will be in grid form you can buy it by the yard for about 1 dollar a yard (very thin paper, (I would buy it to draw clothing onto it and then cut it out and put it on fabric to trace and cut).. then once you get it traced the way you want to, cut it out, tack it to your wall and trace around it! good luck, hope this helped.