Begin by logging onto Google Earth and looking at aerial photos of the town you are trying to draw. Get close overhead images of the town. Save the image by selecting "Edit" on the menu and then "Copy Picture." Open up Photoshop and paste the image into the program. Do this as many times as you need to cover the entire area you want to map. Save the files in such a way that you will know which file you need to go to at any given time.
Travel around the town in question and photograph any major buildings and landmarks in town, such as a statue in a park, a church, school or town hall. Take as many pictures as you need. Download the photos onto your computer and label them according to what they are.
Look at a commercial map of the town. Make a note of all major streets and highways that pass through the metropolis. Take a piece of paper and label the top of it "North." Sketch out the major roads and the major landmarks in the town where they are oriented starting with the northernmost points and working south through the town. Draw this as if looking down on the town at a 45-degree angle. Use both the commercial map and the photos from Google Earth to help. Also, look around the major landmarks and make a note of what the surrounding areas are zoned for, such as a park, residential or commercial. Chances are, you won't be able to fit the entire map on to a single piece of paper. Sketch on several pieces of paper for now, making sure that what you are drawing will line up with what is on the paper next to it. Keep in mind that you are only sketching, so it doesn't need to be perfect yet.
Scan your sketches into the computer at no less than 200 DPI. If you have multiple scans, open them all in Photoshop and paste them into a new file and line them up to complete your map. Create a new layer in Photoshop by selecting "Layer," then "New," then "Layer." Now, starting with the northernmost landmarks, open up the files of the photos you took earlier in Photoshop. Take your drawing tablet and begin on the sketch you made of the landmarks earlier, drawing out the landmark while using the photos as a reference. Repeat this step for each of the landmarks in town, starting with the north and working your way south. Don't worry about scale for a cartoon map.
Once all the landmarks are drawn, label them. Type the name near each of the landmarks, making sure to use a legible font. Create another new layer in Photoshop. Now draw in all the major roads. Do not worry about every single road in the town, as most side streets do not need to be included. But all major roads and any secondary roads will need to be. Two-or-more-lane roads running through town and the streets that intersect them should be included. Any road that runs through the entire town from one end to the other should be included as well as any street it intersects.
Label all roads now, making sure that longer roads are labeled in several places. Label these in the same manner you labeled the landmarks. Create another new layer in Photoshop. Now, draw in generic buildings to represent the commercial, residential, industrial and recreation areas of the town.
Go to the "Layers" tab in Photoshop and delete the original scanned-in sketch layers. Go to the background and color in your map. Make the coloring of landmarks as accurate as possible and use bright green and bright blue for grass and water areas. If you wish, in this step, you can also add small people, vehicles and animals to your map. Also, since the map should still be looking down at a 45-degree angle, at the top you might want to include the sky and some clouds.
Save the image twice -- once as a PDF file and once as a JPEG file.