Unfortunately I don't have great step-by-step instructions and photos as I was caught up in the moment of carving, but I hope that you can draw inspiration from what I've done in carving your next pumpkin!
Step 1: Materials
pumpkin carving tools (small blade, sharp point, scooper, ...)
This year I realized that my pottery tools would make excellent pumpkin carving tools! Pictured are the four that I found most useful for carving details.
For inspiration, I did a google image search and found a drawing of an outline of the SF skyline that would work for what I had envisioned. If I were better at drawing then I would have used a picture that I had taken myself. Print out the drawing and lay it next to your pumpkin.
Step 2: Carving Technique
After you have finished a general outline, use one of the carving tools to chip away at the area within the outline. Do this until you've finished removing the parts of the design that you would like to glow once it's lit up.