I have an Applescript that simply opens a Dialog Box, asks for a user input and runs a Terminal Command and spits out the answer. It works great in AppleScript Editor yet I am trying to work out how I could package this Script File along with an icon to make a Mac App for my personal use. Thoughts.
In Applescript editor File->Save As and choose File Format as Application.
Open Bundle Contents drawer and see the applet.icns file, copy your icon to that.
See "Saving a script as an application" in Applescript Editor help.
In El Capitan at least you can use
osacompile -o MyScript.app MyScript.scpt
to export an an application, do File -> Export and set the drop-down list to "Application"
Open the information window for your Application
cmd+i and drag your icon file (
icns format) onto the top left default icon.