What are the first step to do when entering into the domaining?

This is a tough question. I have sat down and explained the basics about domaining to several people, this takes hours just to scratch the surface. Before entering into domaining, you'll want to find as much information on domain names as possible, find information on sales, what is currently selling, visit dnforum.com (my user id is Rockefeller), visit dnjournal.com, and simply type domain names into google to get as much knowledge as possible. Please do not just jump into domaining thinking that you will be a millionaire within a week. It takes time and money. You will need to find a register that suits you, I personally recommend Dynadot.com. They will let you delete a domain name for account credit within 5 days of registering the domain name. Please feel free to email me and ask if a domain name is worth registering before you spend the money on it. You are bound to register horrible domain names when you first start off. I would never reg a domain name from under you.