Well, with an unmanaged dedicated server, I presume you know how to secure a dedicated server, close unused ports, etc? If not, you definitely should consider securing the server first - this can be done as a "one time" operation, however, you would then need to keep an eye on the logs, and install something like rkhunter to scan your computer from time to time to ensure no rootkits / backdoor / malicious programmes haven't been installed on the server. Thereafter, you would also need to ensure your operating system is kept up to date with the lastest kernel and any patches.
With regard to selling web hosting - using WHM / cPanel, all you would need to do is either create your customers' account manually and then send them the access details, or if you are using some type of billing system such as WHMCS or similar, simply integrate it to create hosting accounts for you through WHM / cPanel once payment is received / processed via your website.
I hope that gives you an idea of what you require / need. If you have any more questions, post them on here ....
Why don't you want to start your own web hosting business with reseller account. I suppose that is the best way get started and get some experience and skills and then you will switch to the dedicated server if needed
Nahh.Dedicated is always better.Just for the beginning try to find any offer at WHT about dedis also buy WHM and all ok.
Clients always prefer owned dedicated server than Cheap-Semi-shared VPS(INCLUDING RESSELER)
Unless you know what you're doing, stay with reseller until you can afford to get a managed server.
One approach, given that you don't want to hear that advice, is to get the box security hardened by configserver.com or platinum servers when you first get it set up. This will save you big time and dollars and uptime as you go.!