My wife and I have absolutely nothing in common other than our children. We have no hobbies we share, we don't like the same kind of movies, we go to two different churches, we have very different backgrounds, personalities and philosophical approaches to life. Having said that, we have been married for 10 years and I consider us to have a very strong marriage. Neither one of us could ever imagine ending the relationship.
If someone wanted to know what the secret to our relationship is, I would just say tenacity. Neither one of us is willing to give up on it. If we have problems, we talk about them as soon as they come up, but we don't expect the conversation to fix anything at that time. We discuss it, then leave it for awhile so we can both think it over and consider the other person's position and whether we can find merit in it. For me, I knew from my wife's personality before we were even dating that she is a very persistent person. She does not give up. It can be aggravating as all heck when we are disagreeing about things or if she gets something in her mind that she wants to do, but I also know that she will go through hell and back before she would let our relationship fail. I trust her and she trusts me.
I think it is tough when you are starting a relationship to really identify objectively the traits in the other person that will work well with you. Likely you will come into it starry-eyed and emotional. It is useless trying to evaluate a relationship while you are in that stage. It takes time to effectively evaluate someone. I think it is very helpful to hold off for awhile before dating someone. If you can hang out with someone as friends for a year or two before dating, you can see what that person is like outside of sexual attractivity.
Another thing is that you have to accept that people change. Even if someone has every trait you could possibly want when you are dating, the likelyhood of them being the same person 5 or 10 years from now is nil. My 24 year old self would probably not recognize my 34 year old self and I know my 14 yr old self would never recognize my 24 yr old self. My wife went from wanting to be a working career woman to wanting to be a stay at home mom to wanting to find some employment that would be a hybrid of the two. At each stage, I never would have imagined that she would have wanted to do something different, she seemed so dead set on filling the role she was currently in. I went from protestant fundamentalist to protestant liberal to agnostic to orthodox. No one would have ever seen that in me 10 years ago. My wife stuck with me the whole way even if she disagrees with my conclusions.
I don't know if anyone is still reading or if this is tl/dr, but hopefully some of this is helpful to someone.