It's simple stuff to do;
Originally Posted by sebastianlacuesta
There are a few different ways to do it, depending on what you are running with gnome. Basically, you need to edit/create; /usr/share/applications/compiz.desktop (with the proper parameters)
then you need to edit one or two settings in gconf-editor, and you're finished.
I personally am using G3+cairo-dock+compiz (no gnome-panel), so i can actually just install a package for archlinux that sets it up with 1 command.
However, it is easy to do manually. you just need to create/edit a .session , and then with GDM you can select it as your session. ie: Gnome-Shell has a .session , so does gnome-fallback , and so does compiz (if you create it), and probably Unity (if you use Ubuntu).
the session file, lists a few things like WM and required components. you can find where they are located, by running;
Here's what they look like;
Gnome Compiz + Cairo-dock (my setup)
IsRunnableHelper=bash -c 'gnome-shell --help | grep -q gdm-mode && /usr/lib/gnome-session/gnome-session-check-accelerated'
I'm sure you can spot the differences