To be perfectly honest I "cheated" when it came to my beryl install. I let those who walked before me pave the path and used an automated install script.
Here is the guide I used, as long as you have a recent Nvidia card and can use the most recent driver, which I am assuming you can, the guide will work fine. The only issue I ran into was that the Nvidia drivers did not load after I rebooted. I was left with no X server (the desktop you are used to seeing) it was easily fixed by the envy script. When I rebooted I was presented with the x server error messages. I viewed/closed those and was left with a command prompt login. Use your normal Mint login and then type the following:
sudo envy
Here is the site for the envy script if you want a little background on what it does:
http://www.albertomilone.com/nvidia_scripts1.html
This will reload the Nvidia drivers and you should have a working Beryl install with no more work that a little cutting and pasting to get the script onto your PC. Other than the hassle of letting the beryl script download and install the Nvidia driver and then having envy do the same 2 minutes later to fix the driver issues it was by far the easiest beryl install I have had to date.
Good luck!
http://wiki.beryl-project.org/wiki/Inst ... ith_nVidia
P.S. If this doesn't work or you want a different guide you may want to peruse the guides here, they are quite comprehensive.
http://wiki.beryl-project.org/wiki/Inst ... _on_Ubuntu