I didn't get married until I was 35. I had many relationships but none that just knocked my socks off, and I was determined not to marry unless I felt that way, even if it meant that I never get married. In fact, I often thought that I would end my days as a bachelor.
One day, I finally met the girl that did knock my socks off and a whole lot more. It didn't take me long to decide I wanted to marry her and it's been up and down since then, but I knew it would not be a picture perfect marriage since I'm a difficult person and any person I could respect would be difficult as well (translated as independent in their thinking). After about the first 4 years of a stormy marriage and getting all of our single ways out of our systems, we've managed to become a pretty good married couple and have been married now for almost 9 years.
I don't really have any advice except marry the girl that knocks your socks off. If it doesn't happen, then you're probably better off single; I know I would be. Marriage is difficult enough and I couldn't imagine being married to someone that I didn't have really exceptional feelings for.