Heh... well... my first critisism would be to save it as a png or jpeg file rather than bmp. Other than that, there is not enough to go on. As far a your specific questions, I would suggest doing doing some VERY general mountains. Simple upside down V's would work and a place holder for further comment. Also, if you want "real" realism, you would need to show some type of temperature zones. For example, deserts will almost always fall between 30 and -30 latitude. But why and where depends on a huge number of factors. Wind patters are a major cause (thus if you REALLY want to make it fairly real you need to set those up) as well as mountain locations (and if you REALLY want to make this fairly real, you need to deal with tectonic forces) AND mountain height.

Personally, i just make crap that I think looks cool and leave the realism out of it...

Oh, and on a side note, if you can, I would suggest making the initial size bigger to let people really zoom in... of course this depends on what your machine can handle and what style(and scale) of map you are going for in the end.