Proper way of changing username in Ubuntu or any linux

I am making use of Ubuntu 12.04 and also made some modification. I will certainly additionally make it a new iso which is tailored ubuntu.

What I intend to ask is just how can I transform my username. There are plenty much arrangement in my existing residence folder. So I do not intend to screw up with transforming username.

So exists any kind of ideal technique or operations to do that?