Here is a well know procedure
1) If your photo is in color, convert to BW using your favorite method. Actually, de-saturing is good enough for this.
2) Duplicate the background layer
3) Do an Image>Adustments>Invert and change the blending mode to Color Dodge
4) Apply a Gaussian Blur, using a radius of about 5
5) My original was a bit faint, so I did two passes of Image>Apply Image. You can do this as many times as necessary to get more detail
6) When you're satisfied, you can do a Merge Visible to create a duplicate layer with all your changes. Then use the Erase Tool carefully to remove any stray lines you don't want.