From my experience (having been in a 2 year LD relationship), I would say you really do have to be very compatible for it to work.
That aside you need some maturity, willingness to sacrifice, understanding and patience as well as the most important ingredient, love for the person you are seeing.
You have to be honest and develop real trust and bond, I would also suggest a broad scope for future plans ie; you move to where they are or vice versa, if there are potential issues with any of these then a LD relationship will most likely not work.
Good luck
