First and foremost, you must know that there is no actual secret.
You may get married when you're 18, 35, or 60.
You may never get married.
I'll admit, some people are more inclined to get married, maybe because of their charming personality, gorgeous features, a headstrong attitude, a heart so big that everyone who meets them falls in love, or maybe someone who wants a family. You get the drift. Relationships, and eventually marriage, can come very easily for some.
The thing that should be quite obvious, but is what I see women (and men) NOT doing, which could ultimately be the "secret"? You have to be going on dates or to events or parties in order to truly meet someone. Notice how I didn't mention online dating or bar-hopping?
With online dating, I have seen many of my friends make a profile (on OkCupid, eHarmony, PlentyOfFish, Match.com, or GOD FORBID Tinder) and then either: A. Use it for two days and quit. B. End up sexting. Bar-hopping may get you a phone number from a hot guy/girl, but at the end of that phone number typically hangs a one-night stand.
Here's what I have found in my own love-life. I went out on the first date with my husband while I was already dating someone else. Now, I'll have you know that I wasn't serious with the other guy, which he was okay with because he knew I didn't want to be in a relationship at that time due to having ended a nearly-year-long relationship just 6 weeks before. I didn't want to get into a relationship with anyone at all. The point here is that I wasn't looking.
I know that many people have known couples that have had trouble conceiving, right? And often times, those couples quit 'trying' and then get pregnant. It happens.
I believe that love and a worth-while relationship can be the same way. Once you let you guard down, you will likely seem more approachable and attractive to others. This issue with a good amount (not necessarily all) singles, particularly women, is that there is a fine line between looking for a partner and being desperate to find one. You can't ask someone if they're going to be your boyfriend simply because you kissed them one time. That's insane.
You can't be afraid to try a new experience or go somewhere that you don't know very many people. Love, dating, and sex aren't things to be afraid of and you don't have to be afraid of not getting married in your twenties. It's okay. There's no expiration date on love.
We all have a certain idea of the KIND of person we are looking for, but if you literally have a list that goes on and on with specifics, don't expect to find any one person who will meet every requirement. The thing with the whole "list" state-of-mind is that what you think you are looking for may not actually be the type of person that you are compatible with. If you keep looking for someone who hits the criteria and you have the wrong criteria for you, as a human being, you may just be repeating the same situation, date, relationship over and over again. This isn't to say that you have no choice in the type of partner that you may marry, but if you let expectations (which could very well be quite unrealistic) block the innate chemistry you may have with someone just because they aren't Ryan Gosling- or Mila Kunis-esque, you could miss out on someone who is perfect for you.
As in all aspects of my life, I believe in fate. If you are intended to meet someone tomorrow and fall in love, so be it. If you're destined to fall in love 30 years from now, just be patient. And if you don't want to ever get married at all, that's fine, too.
The secret? Don't live a life full of fear and just be yourself.