If you are going to create a map for your own fantasy realm, Google maps won't work Maps for role-playing games are properly a better option.
The first thing you need to do is to decide what your world looks like. Create some skretches. Look in Atlas, find old pirate maps or look at some of the online games for inspiration. Remember you get to decide every thing!
If you want a very precise map you will need to decide the scale you want to use. I didn't use any precise scale for my Nidlongdir maps, I created them more as art works, but they still show what I think Nidlongdir looks like. You can draw your map on any thing, use whatever you like. Pencils, ink, paint collage or use a drawing program like Photoshop. My Nidlongdir maps was created as didgital collage from my paintings and digital photos.
Start your map by planning on the landscape, are there mountains, lakes or roads? When you have decided you will need to decide what kind of textures the map should show; like grass, water, sand and rocks. Make some small sketches to try out how the textures will work. You have to decide if you want the map to show on two sides of the paper, or if it might be a part of a larger map, so that you can add more maps later. When you have created the landscape sketch you need to fill in buildings and other importuned details.
Link for old maps