I really think that it helps to have common interests-not that it guarantees that you'll go the distance but I think that it improves the chances. For me it was well after the fact that I realized that my ex and I had zilch in common. I was bagged and tagged the moment I said "I do". I totally agree with making time for one another . It's just too damned easy to get caught up in whatever you're doing and even easier to drift apart.
Also,like many others have said here keep the lines open-talk to one another. Before my ex said she wanted a divorce she put me through a fair amount of bullshit. If she would have just come right out and said "I want a divorce" we both would have been spared a lot of pain. She divorced me three weeks before Christmas-it took a long time for me to start enjoying the holiday again. At the time I coped with this by constantly sleeping. Just in case I'm coming off like I'm putting this all on her I really don't mean to I bear as much if not more responsibility for the marriage's failure as she did. If I ever get married again I'll do a lot of things different and I'll work like hell to get it right.