Geekosphere recently posted a really good OpenVZ cheatsheet with some of the more important commands needed by a sysadmin.  An example is the following to help with VPS creation:

VPS Creation Walkthrough

Create VPS from template:
• vzctl create id --ostemplate distribution-date-arch
Set VPS to boot on host startup:
• vzctl set id --onboot yes --save
Start VPS for further configuration:
• vzctl start id
Set VPS hostname:
• vzctl set id --hostname id.myvps.com --save
Set VPS network settings:
• vzctl set id --ipadd 192.168.0.2 --save
• vzctl set id --nameserver 192.168.0.254 --save
Set password for root user:
• vzctl exec id passwd
Start SSHd:
• vzctl exec id /etc/init.d/sshd start

Read them all at Geekosphere, here.