[veenuisthebest]

The better way is to keep your old domains's nameservers same as new one, and add it as a parked domain in cpanel.

And add this in htaccess:-

RewriteEngine On
RewriteCond %{HTTP_HOST} !^newdomain\.com$
RewriteRule ^(.*)$ http://newdomain.com/$1 [L,R=301]

This will take care of everything. All old URL's would point to exact same location in new domain, it will also take care of www vs non-www issue.