The Post Show Howto Make/Create/Add a New Application Launcher Item into the Main Menu on Linux Lubuntu 12 Lxde Desktop.
To Make the Entire Process Easier to Visualize and Retain the Article Includes the Basic Screenshots of the Essentials Steps Involved.
The Practical Example Shown Up here is About Making a Firefox Nightly Launcher, on the Bottom you Find Link to Installing Firefox Nightly for Lubuntu.
The Content and Details are Expressly Reduced to Give Focus Only to the Essentials Instructions and Commands and Make Tut more Easy & Digestive;)

- Open Terminal Window
- Start the Lxde GUI Creator
sudo su -c "lxshortcut -o /usr/share/applications/nighlty.desktop"
Alternatively you can Create the Launcher also Into: /var/lib/menu-xdg/applications/menu-xdg
- Insert Name and Command
- Set the Launcher Icon
Click on "Change Icon"
Try to Search the Icon between the Defaults One
Now if you Do Not Find it Look:
How-to Locate Icons/Images
Last Click On OK!
- Set the Launcher Categories:
sudo leafpad /usr/share/applications/newapplication.desktop
In Fact there is a Limit in lxshortcut Gui Tool Because at this time it Do Not Set Any Category for the Launcher.
Set the Category:
To Set New Item on the Appropriate Application Menu Section.
How-to Set the Categoy on Launcher
How-to Install Evernote Linux Clone on Lubuntu: