Here's a nifty idea to organize your finder sidebar. Since there are not any separators supported by finder, one man created This creative finder separators to keep your Finder sidebar look tidy. The idea of this separators is creating some fake applications whose icons are transparent and whose names consist of line characters. You can then drag and drop these on the sidebar to give the desired effect.
This trick will keep your finder sidebar visually tidy. The package contains some separators and Apple script that will open your terminal at the location of folder you dropped on it