Hello, this is a nice first attempt. I only think you should try to start from the stretch. First try to make a nice shape (some people also prefer to first map, and after that working on the shape. You should both try them out). Here is an example of a shape:
http://otland.net/f480/minimap-how-make-your-minimap-look-good-139704/. It's mayby not the best tutorial, but you could try to work on one. After that you should try to slowly add details. It might at the start be a bit of taking lot's of time, but you will be able to map faster every time you finished a piece. Just search for a mapping tutorial at this page and make a decision of where you start working at:
http://otland.net/f480/usefull-mapping-links-141623/
Good luck and keep it up!