For my last entry on this topic, I thought I'd write about an important factor in being able to successfully navigate an LDR: YOU! To enter into a long distance relationship, you need to take a hard look at yourself. I don't mean the outside; I'm assuming the two of you are way past any concerns about body/attractiveness issues. I'm referring to some internal characteristics you need to consider because no matter how romantic it sounds, you need more than true love.
Availability: if you don't have time to talk, travel, and meet on a regular basis, the two of you are not going to be able to form much of an intimate relationship. You have to make engaging with your partner a high priority in your life and you have to do it regularly.
Patience: you may likely need a lot of patience to keep a LDR going, especially when you don't know for sure when the relationship will cease to be long distance. You are going to need patience when you don't hear from them when you expect. Likewise, if something comes up that prevents you from connecting with your partner, you need to make sure they promptly know about it.
Trust: if you have troubles dealing with jealousy, you are going to have problems when your mind starts to wonder why you haven't heard from your partner and what they may be doing. Trust in how your partner feels about you and the priority you have in their life, should be the basis of understanding that there is no reason for jealousy coming between the two of you.
Communication: when there is a miscommunication between the two of you, you need to talk it out. If you can't honestly express your feelings, you need to work on that. It might help to write them out ahead of time. Do NOT be tempted to rely on email or text messages to do this. The phone or Skype is much better. And remember, you always lose some of the message when the two of you are not talking face to face (Skype only partially counts).
Life-situation: you need to have a very clear understanding of the set of conditions required before you change your current life-situation and change from long-distance to in-person. Some people think they're ready for a real relationship and only figure out later that they prefer long-distance because they don't have room for a full-time relationship in their life. Others decide they can't move to be with their partner due to other factors (job, kids, etc.). If you haven't got this figured out, you need to be very up-front with your prospective partner. Don't wait until they've quit their job to move to be with you only to find out you're not ready.
I'm sure there are other considerations - what have you discovered?