How to reduce how much area is affected when manipulating vertices? I want to be able to reduce the amount of green area effecting the edges when manipulating the vertices that are selected.

If someone could answer how to do that I would greatly appreciate it.
You can't decrease this area, because it's just space between Edge Loops.





You can expand it by using Proportional Editing (control size by using mouse scroll).





You can decrease it by adding Edge Loops around chosen area.