Start With a Wide Perspective
At this point you should be comfortable with the beginner and many of the intermediate exercises. To get a broad sense of where you are you can tap your cane, stomp your foot, clap your hands, click your tongue, or make a variety of other noises. This will give you a sense of whether you're outdoors or indoors. If you're indoors it will also give you an approximate size of the room and tell you if the room is carpeted, furnished or empty. If you're outdoors it will tell you if you're in a field or parking lot or a grove of trees.
Find a Reference Object
Next, still using this simple sounds listed above, try to get a sense of large nearby objects such as walls, cars and trees. We can explore that object more later and learn about what exactly it is, but for now we will simply keep track of it and use it as a reference point.
Scan for Other Objects and General Envirnoment Shape
Now, using your favorite tongue click, slowly scan the rest of the space around you. Try to determine a distance to the nearest object in all directions. Pay close attention to flat objects as they may represent pieces of larger contoured or angled objects that are less visible. If you see four flat objects at right angles from one another, you are very likely in a square or rectangular room and can orient yourself using these four directions.
Find Hallways and Open Doors
Also be aware of echoic directions that seem to resonate far in the distance and taper off quickly on either side. These generally represent hallways. Open doorways can usually be identified as a "hollow spot", or a "hole" that provides very little response. At this point you should be able to easily identify groves of trees and other foliage, which will tell you if you are at the edge of a field yard or path. Listen for any glass surfaces which could help identify windows and glass doors from the outside of a building. You can also identify doors and store fronts by looking up slightly for awnings.
In essence, no matter where you are, the process will be similar. I'm sure you will find your own specific ways of implementing the scanning process, but essentially, you will want to start wide and narrow your focus toward objects of interest and eventually find walls to track along. Eventually, with practice your need to thoroughly scan the whole room will decrease and your "peripheral" echolocation "vision" will improve allowing you to see objects in many directions all at once.