Before you make something, imagine what you are going to make. Where in the world would such a place be, what is the function of the place, how did it become like this. At the moment your maps don't look natural. For example, mountains never have such a perfect shape. You can loot at tutorials or other maps to look what kind of details you can use or find pictures to get ideas what to make. Anyway, don't forget to make things realistic and functional.