Open Safari in a new window from Dock?
You can't use the Safari icon to directly open a new window (unless you right-click etc, which is boring), but you can create an Apple Script that always opens a new Safari window, assign a fancy icon to this script and place it on the Dock beside the Safari icon. This way you can always choose between the focus on already opened windows (clicking on Safari icon) or create a new window (clicking on the "New Safari Window" icon).

Open Apple Script Editor, make a new document and paste this code:

tell application "Safari"
  make new document
  activate
end tell


Go to File menu, then Export...
Give a name like "Safari - New Window", set a place to save like the "Applications" folder, choose "Application" for File Format and then check Run-Only. Save it.

With Finder, open the location where you just saved this new app. Right-click (or Ctrl+click) the application and go to Get Info menu. Now, download this icon, drag it onto the little "Apple Script" icon on the top left corner of the "Get Info" window already opened to assign the new icon to your app.

Finally, drag the application "Safari - New Window" to the Dock and drop it beside Safari. \o/