There are a lot of other things that you need to do before you even consider slapping up domains superconnected. First and foremost you need to make sure your server is secure and everything is up to date. There as a few threads around here, but I'm not sure any of them necessarily covers everything. One such is
here and I'm sure you can find others with a search of the forums.
Absolute minimum steps you'll want to have done are:
Disable Telnet once you've confirmed you can SSH into the server. Check your SSH version to make sure it's a recent version. Same thing with your PSA and other software on the server. Install and run both chkrootkit and rkhunter to make sure you're starting with a clean server. Install a firewall of some type. Set up up2date so that you can keep the server software up to date, including setting up a skiplist for things that you don't want to have updated that will break Plesk. Change the the Whitelist subnet mask in PSA so that it's 127.0.0.1/32 instead of 127.0.0.8. Change the hostname so that it's a real one. Etc, etc.
A lot depends upon what you want and need out of your server. Personally I always install SIM (System Integrity Monitor) and LogWatch, as they help me to kind of keep an eye on things without having to actively what what's happening on the server 24/7. I always tweak some settings in Qmail too. And ProFTP. And MySQL. And I install ClamAV to deal with virii that come through the email. But those are more personal preferences than they are requirements.
The main point here is that first you need to make sure your new server is secure and that all of its software is current. Get your firewall set up. Close the open relay your mail has by default. Disable Telnet since it's terribly unsecure. Check to make sure there are no rootkits that were on your server before you got it and got it secured.
Then, and only then can you start setting up domains, nameservers, your dns templates and such.