Starting a Death Knight WoW
Starting a death knight is a little different to starting a character of most other classes.
As a hero class, death knights do not start at level 1, instead starting at level 55. Death knights also do not spawn at their corresponding racial starting area, but instead in a necropolis in an instanced version of the Eastern Plaguelands called Acherus: The Ebon Hold, which includes a dedicated questing area and class trainers.
The death knight is initially required to complete a special series of quests in this area. By completing these quests, players learn how to bend the power of the death knight to their own will, and after they have mastered this, the death knight is then capable of going to any other area.
Choices to Make for Your Death Knight
Many players like to choose the race with the 'best' traits and abilities for their class. Here is a brief overview of how the racials look from a death knight's perspective.
Night Elves and Draenei bring the best abilities for PvE solo play and leveling, because they allow you to escape or heal, respectively. Nature and especially Shadow damage are both common, making those resistances quite useful. The increased dodge or hit rating are both useful in end game play.
Horde race traits are very balanced throughout the bank. Trolls are arguably the weakest, because you can heal quite well on your own already, and beasts are not that common an enemy (and often not as annoying as humanoids, who are often casters or have silencing abilities).
In the end, race is a rather minor consideration. If you're min-maxing, Orcs are the strongest Horde race for DPS and Tauren the strongest for tanking. For the alliance, Night Elves are the best tanks and Humans the best DPS. But go with whatever race you feel like, whether for its racials, its looks, its personality and flavor, or any other reason you can think of.