Make sure you can use their SMTP servers for outgoing email. Many hosting and domain name registration providers will not let you use their SMTP servers for sending emails. They assume you can send email via your internet server provider’s SMTP servers. However, a great many ISPs and broadband providers will only let you use their SMTP servers on their branded email accounts (i.e. [email protected]). This means that if you use your own email address (i.e. [email protected]), you won’t be able to send email via their SMTP servers. There are workarounds but you shouldn’t have to go to the trouble.
By definition, a domain name is simply a human readable form of an IP address. In function it is the destination that you type into a web browser in order to visit a website, such a www.google.com. Metaphorically, it is very similar to how you would scroll to a contact in your cell phone rather than manually dialing the person by entering their full phone number; the phone number would be an IP address and the saved contact would be a domain name. Always buy a domain with a reputable domain registrar.
Be extremely cautious while communicating with the owner. Even if you casually agree to buy the domain via email, the communication might be used against you in court as a legally-binding contract should you change your mind. Until you’re absolutely certain that you want to make a deal, agree to buy the domain provided that all the terms are agreeable. This will leave you an escape hatch if things go south.
You should also avoid words that have more than one spelling if your visitors are likely to be confused and mistype the name. Alternately, you can buy both versions of the name and direct visitors from the one you like less to the preferred name. While you do want a short name (see below), don’t go for something so cryptic that people have a hard time remembering it. Word of mouth is a powerful marketing tool and you want to make it easy for people to tell their friends about your site.