It's not so much about looking for it as it is about staying open to it.

no one is going to knock on your door unless they know you are there

I think you have to be open to finding someone. You have to put yourself out there and be willing to get your heart broken. You have to find a way to meet people and get to know them. You never know when you will meet someone that just has that certain "spark" that you are drawn to. It may be someone you speak to and strike up a conversation with in the grocery store or someone that you have met online. You just never know. You have to be willing to take that "leap of faith" though. You just never know. I think it really is about meeting the right person. But I don't think there is just one right person for any of us.

Spark and chemistry is the starting point

I agree with others, if you are not looking love will find you, no time and no place . . . As ms Dessen said, it happens
Accidentally

Could be around the next bend

It does seem to happen when one just chills and waits a while. ( Just need to be careful of people who are not honest about who they are and what they want.)

Either way.

The important thing to me is leaving yourself vulnerable and open to it as it passes you by.

I agree with this...

I think for me when I am actively seeking, I tend to make choices that aren't wise for the long run.

When I am just "being" is when I have found the love and so much more.

I could not have said it better