I was in a LDR for about a year and a half, with someone that lived across the atlantic ocean... I very rarely got to see him! We suffered some terrible setbacks, including him getting deported from my country the first time he came to see me
Not his fault either - they decided that since he had a girlfriend here, and no job back home, they couldn't risk him entering and not leaving.
Now we are married and living together, and are extremely happy. I do not believe that I could've found anyone I wanted to be with more than him, and it was worth every lonely night and bureaucratic paperwork nightmare.
Things that we did:
Talked every night on skype with webcam. Doesn't have to be sex/relationship based... share what you did that day, complain about work, try and get to know each other. I used to ask him those silly 'meme' surveys that go around on Livejournal and MySpace, and then ask him questions about his answers. Reason: I think if you focus on just the 'golden end' when you get together, you're in agreement, but you never find out who they really are apart from how they are about your relationship. When you do finally meet up and live together it can quickly fall apart because you have nothing in common any more!
Always had a planned date for when we would next see each other, so we always had something to look forward to and plan. Although we didn't know when we would be able to live together, we did at least know it would only be 3 months or whatever until we next saw each other.
Told each other everything. Everything. Tiny flaws, past relationships, stuff we were insecure about. Having read Steve's book I would say we were aligning ourselves not just with love (which was a given) but with truth and power as well. Both of us were courageous about telling the other about things that would have been much easier to leave alone. Because we began from a position of great friendship, I think it was easier. Part of that, for me, was facing up to my issues about sex. I had a deeply unpleasant experience when I was 18, and since then had described myself as asexual. It took a loooooong time to work through that, and a lot of courage, love and patience on both our parts.
Trust them. He was still in contact and fairly close to his long-term ex girlfriend, and had several female friends. But I never ever mistrusted him. He had been cheated on before, but he trusted me.
I think honesty and openness is so important because it is so easy to lie, be deceitful or just 'omit the truth' in LDR.
Finally, of course, we both had other things in our life. I had college and then work, whilst he had work and his family. We both had strong friendships with 'real-life' people. We were able to vicariously share happy events with each other. Spend all your time moaning about how you can't be together and you will associate the other person with moaning and complaining! Better to be happy and excite each other, rather than wallow in what you are missing.