I was in a LDR for half a year before we moved it to a RLR. To repeat a bit what the other members have said, communication is extremely important. Every day, even if it's a quick word or if for some reason phones aren't available (in this day and age... it happens) emailing replaces it.
Settle a routine, fixed times of the day in which you absolutely talk. If for some reason one of you can't make it to the appointment, explain beforehand. Adding to that, a surprise text message or email always made my day.
For us, tasking was very important as well... Establishing the nature of the relationship from the start forms a recognizable pattern for yourself that, if you are both committed to the relationship, will make the initial adjustment easier when (if) meeting personally.
Another thing, and this might seem silly but I found it deeply important. If you have doubts, questions, a bone to pick with your partner speak up immediately. Forgetting that voice modulation doesn't translate to writing is easy and misunderstandings can be fatal when you're on a LDR.