Nice one Afsal!
Some thoughts about the project.
There's no need to create your own icons, you can use adwaita-icon-theme [1]. Take a look also to gnome shell CSS code [2] for more information. Some elements of your project changed in GNOME 3.14. E.g volume menu is now on system menu (old user menu) with Location, User and System menu actions.
You can also fork Ubuntu online tour [3] (in my opinion is a good start for what you want to do). You have the basic structure and with some adjustments you can convert it for GNOME shell.
Tom