Just tried to root my GSM Galaxy Nexus manually several days ago. I followed the instruments on the XDA forum here and here. File used are placed in my skydrive.
- Download root package (SuperSU-0.93-Busybox-1.20.2.zip)
- Download CWM (recovery-clockwork-188.8.131.52-maguro.img)
- Reboot into Fastboot Mode: Power off your device and (Power + Volume Up and Down)
- Unlock the bootloader if locked (fastboot oem unlock) then reboot into fastboot mode again
- Temporarily flash CWM (fastboot flash recovery recovery-clockwork-184.108.40.206-maguro.img)
- Boot into recovery (Press Volume Up twice until you see “Recovery mode” then press the Power button)
- Using CWM recovery, install SuperSU-0.93-Busybox-1.20.2.zip that you downloaded in step 1. The file should be placed in your /sdcard folder.
- Reboot into the OS
- You are now rooted