Very simple map but a nice start! Later on you can experiment with different colors and try to work in a bit more detail. There is a great crew up here that can offer tons of advice to do just that!
- I would suggest a larger map. Your appears a bit small and as a result you won't be able to get much detail in there.
- Color of the earth. It looks a bit orange to me.
- I would save your maps as Jpeg instead of BMP. You will be able to make much larger drawings and they won't take up a ton of hard disk space to save them.