sure, one thing you have to make sure is that nothing in nature(notice I'm saying nature, so that doesn't mean fences or anything else that is man made.) is square so your maps shouldn't be square. A simple way to do this with mountains or a beach is to day the basic tile of that land form and just make a random line, then go ahead and fix it and do what ever you need to do. If you look at my maps you can see that nothing is more than 5 tiles long.
P.S. If done right your map should look horrible at the start =]