Launchers are .desktop files stored under /usr/share/applications folder.
If you happen to have downloaded and extracted eclipse in a folder somewhere like /home/user/eclipse, it would be a hustle to always navigate there when you want to start eclipse. This is also true for any other application that is not installed natively via apt or software center. You probably want it in the favorites menu in gnome or the unity launcher with the eclipse icon so you just click on it ;-). Here is how to:
sudo nano /usr/share/applications/eclipse.desktop
Then paste the following in that file (click inside to select all):
Ctl+o to write to file, then Ctl+x to close file.
You can replace all instances of eclipse hereinbefore with any other launcher, so long as the paths are correct.
Hit the super-key/launcher-key (aka the windows-key), or hover the mouse to top-left corner if using gnome and type eclipse(or the app you added) to search, right click the launcher and click “add to favourites” if you are using gnome, or drag-drop to the unity launcher if you are using unity.
To use gnome pannel, basically a GUI method, install it without having to install all the recommended and not needed packages:
sudo apt-get install --no-install-recommends gnome-panel
Then launch it:
gnome-desktop-item-edit /usr/share/applications/ --create-new
A window will pop up with a form to fill for the above details :).
In case you are wondering about the wallpaper,
pencil madness is pretty cool to tinker with when you get tired 😛