We have one major tip that most "newbies" are not aware of.
1) Do not infringe on trademarks of others!!!
Thousands of companies own rights to names all around the world. An infringement would occur if you are using the same or "confusingly similar" name in the same "Goods and Service" class. An example below
We register "tinyurlme.com" and want to start a "Link Shortening Service". All is well, traffic is building and we are in heaven! The next week [SLAP] you receive a C&D (Cease and Desist) from Gilby Productions ordering you to shutdown or else. You continue to ignore these emails and the next month you get a letter in the mail ordering you to appear in court, charged with "Trademark Infringement"!
See Gilby Productions owns the trademark to "Tiny Url", but you didn't know before hand.
In summary: Always check the USPTO before you register a domain to see if anyone else owns the rights to the same you want to register. If the name appears but is in a different class for the G&S your safe. Anything to due with internet software, websites and such are under IC 042 & somtimes IC 035 for advertising and business & IC 009 for downloadable software.
Anyway, there is a lot more to trademark law which you can find around the internet!
Check the USPTO before you register a domain!