An example is this overhang roof. If you deleted those edge loops from the middle, the model would still look the same but be using less geometry. The fundamental thing to keep in mind is that your model is really nothing but vertices. And a vertex is three numbers (0,0,0) that define a point in 3d space. So, the fewer…
Please check out this tutorial. It shows exactly what you want to do. See how he has a straight texture and curved surfaces: http://www.thiagoklafke.com/modularenvironments.html
If it for a game? How big will it be? What platform? On youtube look up Warren Marshall and also polycounts own @PixelMasher for tutorials showing the basics of video game environment art. Beyond that only very general critiques can be made such as: you have many edges which, if deleted, would not effect the silhouette. So…