The answer depends upon ourselves.
We first must know what it is WE want in order to be able to recognize when we have found it.
Another factor is we are constantly evolving as we mature. The perfect love at 18 may have been having someone who is beautiful/handsome with a great sense of humor. However at age 32 we might have added some additional requirements as to what constitutes our "true love". Until we have our “permanent list” of requirements our idea of what a “true love” is will continue to change. Therefore we’re likely to define “true love” based upon where we are in a particular phase of our lives. The most difficult part of relationships is in (selecting) the “right mate” for ourselves.
Each of us Chooses our own friends, lovers, and spouse. If you go to the store to purchase an apple but buy an onion instead, whose fault is that? Many of us will make a list of the traits we want or need in a mate and then we'll throw the list out of the window because we've found "chemistry" with someone. After we've invested time and emotion we come to realize they are not what we really want so we either try to "change them" or find a way to blame them for (the choice we made) when it does not work out.
I believe we find our true love after we've done our share of introspective thinking to determine what type of mate we want for the long haul.
The next step is to have the courage and patience to not deviate from "our list of requirements".
The third step is put yourself in the shoes of the person you want to be with. (What type of occupation, hobbies, organizations, gyms, online dating, nightclubs, vacation destinations, restaurants...etc would he or she likely to be interested in)
The fourth and final step after you have created your ideal "profile" is to BE THERE! Simply put, you have to be where "they" are, travel in the same types of circles.
Opposites may attract for a short time. However Like attracts Like for a lifetime. Generally speaking water seeks it's own level.
Ulitmately we are looking for someone who wants what we want out of life. When two people aren't on the same page a relationship is doomed.